Mike Tyson will only learn if he will be allowed into the UK to box British fighter Julius Francis when he arrives at the weekend.

And the American boxer appears set to challenge officials to force him to turn back from Heathrow Airport on Sunday.

The bout is due to take place in Manchester on 29 January, but it has been thrown into doubt following the UK authorities' decision to take issue with Tyson's criminal record.

Prime Minister Tony Blair has told the Commons that the matter would be dealt with by the Immigration Service in the "proper way".

A Home Office spokesman confirmed the situation in a fax to promoter Frank Warren on Tuesday.

"The decision must be made by an immigration officer upon his [Tyson's] arrival.

"Mr Tyson can ascertain in advance if he is qualified by applying to a British Embassy."

Under British rules, anyone convicted of an offence which would carry a 12 month jail term in the UK is not allowed into the country.

The American was jailed for rape in 1992, serving half of a six-year sentence.

There has been talk of Tyson taking on another fighter in Germany if he cannot box in Manchester.

But Warren says there is no chance of moving the clash with former British champion Julius to a venue outside the UK.

Asked if he would consider taking the fight to the US, Warren told BBC Radio 5 Live: "It's too late to arrange, it's two weeks away.

"We've laid out a lot of money - non-refundable deposits, air fares and so on - and I'm not accepting it because the way this has been handled has been very, very bad."

But he added : "I do believe that common sense will prevail and this will be sorted out to everyone's satisfaction."

A Home Office spokesman said: "The rules state that entry is normally refused, except where there are strong compassionate reasons."

'Political whipping boy'

The matter is already the subject political debate, with a number of candidates for the London mayoral election opposing Tyson's entry.

In the Commons on Wednesday, the chairman of the parliamentary all-party boxing group, Labour MP James Wray, asked Mr Blair to ensure that there would a "fair and just decision" in the matter.

"I am appalled by the way the four candidates for the London Mayor have used Mike Tyson as a political whipping boy," said Mr Wray.

"I am also concerned regarding the economic effect it will have on the hoteliers and the service industry in Manchester."

Mr Blair replied: "I think anyone would be ill advised to use him as a whipping boy.

"This is being dealt with by the Immigration Service and they have to deal with it according to their rules in the normal way - that is the proper thing to do, to play it by the book."

On Tuesday, Mr Blair's spokesman had told reporters: "As I understand it, the room for discretion is very, very limited."

As a US citizen, Tyson does not need a visa to come into the UK or a work permit to take part in a boxing match.

But for the fact that he is extremely well-known, he would probably have been able to enter the country unchallenged.