A BALACLAVA-clad raider threatened a female cashier with a screwdriver before taking off on a mountain bike with hundreds of pounds in cash. 

The robbery took place at about 6.50pm last night at the post office, which is in a Premier shop, in Ipswich Road, Colchester. 

It is understood the cashier was working alone at the time. 

Detectives are now searching for the robber, who is described as 6ft tall.

He was wearing a dark green coat, dark-coloured trousers and dark-coloured gloves.

An Essex Police spokesman said: "We are appealing for information following a robbery in Colchester

"A man went into the Post Office in Ipswich Road at around 6.50pm on Wednesday, October 11, threatened a female member of staff with what is believed to have been a screwdriver, and stole a three-figure sum of cash.

"He then rode off on a white mountain bike."

Anyone with information on the incident or witnessed the raider fleeing should contact DC Trevor Clark at Colchester CID on 101 or Crimestoppers anonymously on 0800 555 111.