FOUR people have been sacked and another two have resigned as part of an investigation into a potential stamp fraud at a call centre, The Northern Echo can reveal.

The six are understood to have peeled unfranked stamps from mail sent – by students around the world - to the Student Loans Company (SLC) offices in Darlington.

Some were sold on eBay – including one collectors’ item, which allegedly fetched more than £1,500 – according to the whistle-blower who brought the scam to light.

The SLC employee, who asked to remain anonymous, said the investigation is the subject of intense speculation at the company’s call centre at Lingfield Point, in Darlington.

SLC bosses confirmed that an investigation is under way and said they were taking the matter ‘very seriously’.

The company said stolen stamps were being ‘reused’, but declined to comment on speculation about them being sold online, as the investigation is ongoing.

Royal Mail has been informed of the investigation and the SLC said information gathered would be shared with police.

The deliberate re-use of stamps can be considered an offence under the Fraud Act 2006.

The source said: "Some of them are special stamps, one was a collectable that sold for £1,600 – it hadn’t been franked, so they were just able to tear it off the envelope and put it on eBay.”

The whistle-blower said there had been no announcements from bosses at the SLC in Darlington, further fuelling speculation.

He added: “I think the thefts are disgusting, it’s clearly gross misconduct and a breach of trust.

“Anyone prepared to tamper with incoming mail is clearly breaching the company’s trust and I am sure the students would not be happy to think they were putting stamps on their post in good faith and someone was selling them online.”

An SLC spokesman said: “The Student Loans Company is investigating a number of alleged incidents of theft at its Darlington office.

"Some members of staff involved in these incidents have left the company.

"We are taking this matter very seriously and are continuing our investigations.”

A Royal Mail spokeswoman said: “We endeavour to cancel all stamps and would encourage customers not to re-use a stamp that has not been cancelled.”

The SLC employs about 1,200 staff at its Darlington call centre.