A gang which conned vulnerable and elderly people out of thousands of pounds in a telephone scam have admitted their crimes.

The six men, all from London, posed as police officers and bank staff investigating supposed attacks on customers' accounts, Essex Police said.

They convinced victims to hand over bank details and PIN numbers before arranging to collect their cards for "forensic tests".

It is the latest case in the growing problem of courier frauds with police forces across the UK warning members of the public to be on their guard against such bogus calls.

People across East Anglia were targeted between March and July this year, the force said.

A victim in Dedham, Essex, lost £5,000 while a family in Steeple Bumpstead in the county lost £7,000.

Five of the men were arrested in a series of raids in north London in July led by officers from a special task force set up by the Eastern Regional Special Operations Unit to deal with the rapidly-spreading frauds.

An Essex Police spokesman said: "More than 80 officers from Essex, Hertfordshire, Bedfordshire, Suffolk, Cambridgeshire and the Metropolitan Police Service were involved in the searches of six addresses in the Camden area.

"Numerous phones and computers were seized by the regional team, which was set up to investigate hundreds of frauds and attempted frauds being carried out across East Anglia.

"Elderly or vulnerable people were targeted by thieves who posed as police officers or bank staff who told their victims that their bank accounts had been infiltrated by thieves."

Mohammed Miah, 22, of Coopers Lane, King's Cross; Mohammed Hussain, 22, of Malden Crescent, London; Motahir Rahman, 23, Kiln Place, Kentish Town; Mohammed Ahmed, 22, of Hemingway Close, Gospel Oak; and Dedar Ali 20, of Cressfield Close, London, all admitted conspiracy to defraud, Essex Police said.

Salam Uddin,18, of Hemingway Close, Gospel Oak, admitted a separate charge of conspiracy to defraud at Cirencester, Gloucestershire, in January.

They appeared at St Albans Crown Court on Monday and will be sentenced at the same court on December 4.