Manufacturing giant Siemens is to invest £160 million in wind turbine production and installation facilities in the UK, creating 1,000 new jobs.
The German firm had been working on plans to invest £80 million, which would have led to 700 jobs, but it has decided to revise its plans, giving a boost to the offshore wind industry.
The work will be spread across two sites comprising the previously announced Green Port Hull project construction, assembly and service facility and a new rotor blade manufacturing facility in nearby Paull, in East Riding.
Siemens will invest £160 million across the two locations and its port partner Associated British Ports (ABP) is spending a further £150 million in the Green Port Hull development.
The combined investments of £310 million will create up to 1,000 jobs directly, with additional jobs during construction and indirectly in the supply chain.
Siemens said it will be the first manufacturing plant of its kind for the firm's next-generation blade technology designed for wind turbines.
Each rotor blade is 75 metres long and when rotating covers an area the size of two-and-a-half football pitches.
Michael Suess, member of the managing board of Siemens and chief executive of its energy sector, said: "Our decision to construct a production facility for offshore wind turbines in England is part of our global strategy. We invest in markets with reliable conditions that can ensure that factories can work to capacity.
"The British energy policy creates a favourable framework for the expansion of offshore wind energy. In particular, it recognises the potential of offshore wind energy within the overall portfolio of energy production.
"The offshore wind market in Great Britain has high growth rates, with an even greater potential for the future. Wind power capacity has doubled here within two years, to roughly 10 gigawatts. By 2020, a capacity of 14 gigawatts is to be installed at sea alone to combine the country's environmental objectives with secure power supply. Projects for just over 40 gigawatts are currently in the long-term planning."
Roland Aurich, chief executive of Siemens, said: "Being able to further increase our presence in the UK with this significant commitment is great for Siemens, for the UK economy and for future generations, who will benefit from more secure and sustainable, low carbon energy."
Siemens employs around 13,700 workers in the UK, including 4,000 in the energy sector.
Energy Secretary Ed Davey said: "This deal is excellent news for the people of Hull and the Humber, the UK, the wind industry, and our energy security. We are attracting investment by backing enterprise with better infrastructure and lower taxes.
"As well as helping to keep the lights on and putting more than 1,000 people in work, this deal means we will help to keep consumer bills down as we invest in home-grown green energy and reduce our reliance on foreign imports.
"This deal shows our strategy for offshore wind is working; bringing investment, green jobs and growth, and helping keep Britain the number one country in the world for offshore wind.
Leader of Hull City Council Stephen Brady, said: " The project is very complex and it has taken a great amount of time and effort by many parties to get to this stage. The team at Hull City Council have played a major role, working with Siemens and ABP to make the development a reality and confirming Hull as the cornerstone in establishing the Humber as the UK's Energy Estuary.
"There is now an optimism and confidence in the air throughout the city which we have been working towards for many years."
Greenpeace UK executive director John Sauven welcomed what he called a "milestone" in the development of the UK's offshore wind industry, saying it would create green growth, skilled jobs and the prospect of a growing UK supply chain.
Mr Sauven said: " This will reduce the costs of producing clean energy technologies, whilst maximising the benefits for our economy."
RenewableUK chief executive Maria McCaffery said: "This is a major coup for the British wind industry - it's the green-collar jobs game-changer that we've been waiting for.
"Attracting a major international company like Siemens to the UK, creating 1,000 jobs manufacturing turbines at two sites in Yorkshire, proves that we can bring the industrial benefits of offshore wind to Britain.
"This is just the start - where Siemens are leading, a cascade of others will follow - and we'll see very significant growth in the UK supply chain."
Friends of the Earth Yorkshire and Humberside campaigner Simon Bowens said: "This world-class manufacturing hub for the offshore wind industry will be a massive boost for the region and our environment.
"This investment, which is going ahead despite the uncertainty created by Government, is exactly what's needed to develop the UK's huge renewable energy potential, create jobs and reduce our dependency on dirty fossil fuel imports from abroad.
"It's time to end the Chancellor's fixation with fracking and squeezing out 'every last drop' of North Sea oil, and focus on building a clean future based on energy efficiency and renewable power."
The leader of the East Riding of Yorkshire Council welcomed the announcement as a "historic moment for the Humber region".
Stephen Parnaby said: "This is certainly one of the proudest moments in all my years as leader of East Riding of Yorkshire Council.
"The wide-scale economic benefits this investment will have for East Riding businesses cannot be overstated. It is also excellent news for East Riding residents, with the development providing employment opportunities in an emerging sector.
"The council will continue to work alongside Hull City Council and the private sector to provide support for local businesses in becoming part of the renewable energy supply chain and to develop the skills of the local workforce to maximise the benefits of this investment and ensure that as many of these as possible remain local to help grow the economy of the Humber."
Mr Parnaby added: " I am absolutely delighted with this news. It has been a long road from this proposal first being mooted to it finally getting the green light to go ahead.
"It is an historic moment for the Humber region, certainly unrivalled in recent history, and will create an initial 1,000 jobs and thousands more in the supply chain and related business, providing both short and long-term economic benefits that will help transform the area's economy."
Caroline Flint, shadow energy and climate change secretary, said: "This investment will be warmly welcomed across the Humber, not least by Hull's MPs, councillors and local businesses who have campaigned for it ever since Siemens announced its decision to invest in new manufacturing facilities in 2010, under the last Labour government.
"All too often in the past the UK has missed out on investment because of the Government's mixed messages on clean energy. As this decision shows, the UK has the potential to be a world leader in clean energy. Labour would provide the certainty and clarity investors need to create more jobs and manufacturing in Britain by setting a decarbonisation target for 2030."
Nicola Walker, the CBI's director for business environment, said: "This investment is great news for Hull with 1,000 new manufacturing jobs created. It shows the UK is well placed to become a world leader in the construction and development of renewable energy generation.
"Getting Royal Assent for electricity market reform was hard work, but now we're starting to see the benefits of making the UK a more attractive place to invest."
Hull Council leader Stephen Brady, said: "This is a huge milestone in our shared development aspirations for Hull and a great step forward towards one of the major projects in our City Plan, which aims to deliver substantial inward investment and create several thousand new jobs in the City over the next 10 years.
"The project is very complex and it has taken a great amount of time and effort by many parties to get to this stage.
"The team at Hull City Council have played a major role, working with Siemens and ABP to make the development a reality and confirming Hull as the cornerstone in establishing the Humber as the UK's Energy Estuary."
Unite national officer Kevin Coyne said: "The country's wind power industry has been blown back on course thanks to Siemens' £160 million investment. One thousand green collar jobs is a lifeline for manufacturing in the Yorkshire and Humber region and it's great news for renewable energy and for Britain's economy.
"Unite looks forward to working with Siemens to make the facility a green manufacturing success story."
Later, David Cameron arrived in Hull and was shown around the site of the proposed development at the docks.
The Prime Minister was joined by Mr Davey as he walked along a windy Alexandra Dock in a hard hat and high-visibility jacket, accompanied by executives from Siemens and ABP.
He said: "This is a massive investment for Hull but also a big investment for Britain.
"We already have a world leading wind market but now we're going to be making the turbines and the blades here in Britain - a nd the chance to have a world leading industry employing thousands of people across this area.
"A real change for Hull and for Humberside. And great for Britain too."