He seemed like a nice guy, I guess, but I was definitely surprised when he wanted the change

Big Issue seller Jaz Walter on Jack Straw

At least that was Mr Walter's version of events - the Home Office later insisted he had offered the change to Mr Straw.

The home secretary was on an official visit in London when the seller stepped forward to offer him a copy of the magazine, sold by and to help support homeless people.

Mr Walter, who has been selling the Big Issue for a year and a half, said: "I was very surprised to see Jack Straw but I thought I would ask him if he wanted a copy anyway.

"He gave me a �10 note and at first I thought 'He is being generous'.

"But then he immediately asked me to give him his change back.

"I only had �8 on me, so he took that from me in the end and walked off.

"He seemed like a nice guy, I guess, but I was definitely surprised when he wanted the change."

The Big Issue has featured big-name interviews, such as this with Tony Blair in 1997

Mr Walter said the extra cash could have come in useful as he is sleeping on a friend's floor and cannot claim benefit.

"But then I suppose he did give me �2 for it at the end of the day, though I'm not sure he wanted to," Mr Walter added.

However, a Home Office spokesman later said Mr Straw did not ask for the change but that it was offered by the magazine seller.

"The home secretary often buys a copy of the Big Issue and was happy to buy one today," said the spokesman.

"He was glad to have a chat with this gentleman, who offered to give him change, so he actually agreed to buy the magazine for �2.

"He turned round and various people went into their pockets to find a smaller note to break into, and the seller said not to worry because he had the coins."

The purpose of Mr Straw's trip to King's Cross was to see an initiative aimed at tackling street crime.

Government policy

Some may say Mr Straw's request for change from Mr Walter is in keeping with his previous pronouncements and government policy on beggars and the homeless.

As shadow home secretary Mr Straw attracted a deluge of criticism when he declared a Labour government would reclaim the streets from "beggars, winos, addicts and squeegee merchants".

In July last year he proposed fast-track deportation hearings for asylum seekers convicted of begging.

The move was mainly prompted by concerns about aggressive begging on London's Underground.

Christmas campaign

Before Christmas, a government campaign was launched urging the public to donate money and time to homelessness charities rather than giving cash to street beggars.

The home secretary could also be said to be following his leader's example.

Tony Blair, in the run-up to his 1997 election victory, strongly backed "zero tolerance" policing tactics against homeless petty criminals and admitted that he never gave money to beggars.

Those comments were made in January 1997 - during an interview with the Big Issue.