THE health secretary Alan Johnson became the latest cabinet minister to be embroiled in a scandal over donors last night after he was accused of accepting cash through a proxy.

A student, Waseem Siddiqui, said he was asked by his brother, a local Labour party official, to write a cheque for £3,334 towards Johnson’s failed bid to become deputy leader.

Johnson admitted last night that the gift was one of four donations he had received that have not yet appeared on the register of the official watchdog, the Electoral Commission. There are conflicting accounts about when his campaign notified the watchdog.

The revelations will cause severe embarrassment for the health secretary, coming just days after the resignation of his cabinet colleague Peter Hain, who faces a Metropolitan police inquiry into £103,000 of undeclared donations for his own failed deputy leadership bid.

It was reported last night that Harriet Harman, the winner in the deputy leadership race, will be interviewed by police investigating donations made to her campaign by a proxy for the controversial millionaire property developer David Abrahams.

Siddiqui, 50, from Pakistan, who has lived in Croydon, south London, on a student visa for the past three years, said his brother Ahmed Yar Mohammed, who is treasurer of Croydon Central Labour party, told him to write the cheque in June and then gave him the money. “He said, ‘You write a cheque, I write a cheque for that, for the Labour party,” Siddiqui is said to have told the Sunday Mirror newspaper. “That time I have no money, no job.”

Siddiqui said he neither knew who Alan Johnson was nor had any interest in the Labour party.

Johnson’s camp said last night that Siddiqui was known by volunteers in his campaign and lives near the minister’s south London home. He is named on the electoral register and is eligible to make political donations. However, the 2000 elections act forbids donations to be given by third parties unless the real donor is declared to the Electoral Commission.

Although Johnson says his campaign team first submitted details of the donation to the commission in the summer, sources close to the watchdog said it was not informed until December, when the details were resubmitted.

Johnson was first told about the problem with the proxy donation yesterday and according to staff was “shocked”.

“We had no reason to believe the donation came from anyone other than Mr Siddiqui,” a spokesman said.

“When finalising our accounts last year we double-checked that donations to the campaign were properly declared. We confirmed that we had notified the Labour party and paid the necessary levy on all donations. We also notified all donors that their name and their donation would be made public and appear on the Electoral Commission website.”

But there were unanswered questions last night about why, if Johnson had registered the donation from Siddiqui with the watchdog, it had failed to register it.

The commission is carrying out checks on the donation, which if registered in December would have been months late. Three other donations to Johnson did not appear on the commission’s website, including a donation from AA Care Homes for £1,500. Dr Anwar Ansari, the vice-chairman of Croydon Labour party, is listed as a director of the company, which had previously given £1,660 to Johnson. Ansari’s firm owns the flat that Siddiqui rents in Croydon but the doctor denies he had anything to do with Siddiqui’s donation.

“The commission undertook to check their records and we immediately resubmitted forms for the four donations so there could be no doubt of our intention to register these donations,” the spokesman for Johnson said.

The other donations were from Sonny Leong (£2,000), Siddiqui (£3,334) and Songlines Ltd (£2,500).

However, Johnson’s campaign admitted that the Songlines donation had not been notified to the Office of the Parliamentary Commissioner for Standards.

Undeclared donations claimed Hain’s cabinet career last week after he was forced to resign as work and pensions and Welsh secretary. Hain had failed to declare £103,000, some of which was channelled through a little-known think tank. The Electoral Commission asked police to investigate after a “thorough review of the case”.

Police are already investigating £650,000 in donations to Labour from Abrahams, the Newcastle property developer. He channelled £381,850 to the party over the past four years through his secretary Janet Kidd and Ray Ruddick, a builder who worked for him. Kidd also donated £5,000 towards Harman’s campaign.

Labour party sources said the prime minister had recently been made aware that Johnson was discussing donations with the Electoral Commission. Mr Brown is apparently “relaxed” about the situation.

Times Recommends

• In Margot Fonteyn's footsteps
• Forget beautiful people, let's have wonky Brits
• Fundamentalist brew: faith and power