The government has given an initial rebuff to the campaign for a pardon for Alan Turing, the brilliant British 'father of the computer' whose career ended in tragedy after a gross indecency conviction at a time when gay sex was against the law.

Signatures are gathering on an e-petition for a pardon but the justice minister Lord McNally used the precedent argument to discourage the notion in the House of Lords.

Asked by the Liberal Democrat Lord Sharkey whether a pardon would be considered, to mark this year's centenary of Turing's birth which is the subject of international scientific celebrations, he told peers:



The question of granting a posthumous pardon to Mr Turing was considered by the previous Government in 2009. As a result of the previous campaign, the then Prime Minister Gordon Brown issued an unequivocal posthumous apology to Mr Turing on behalf of the Government, describing his treatment as "horrifying" and "utterly unfair". Mr Brown said the country owed him a huge debt. This apology was also shown at the end of the Channel 4 documentary celebrating Mr Turing's life and achievements which was broadcast on 21 November 2011. A posthumous pardon was not considered appropriate as Alan Turing was properly convicted of what at the time was a criminal offence. He would have known that his offence was against the law and that he would be prosecuted.

It is tragic that Alan Turing was convicted of an offence which now seems both cruel and absurd-particularly poignant given his outstanding contribution to the war effort. However, the law at the time required a prosecution and, as such, long-standing policy has been to accept that such convictions took place and, rather than trying to alter the historical context and to put right what cannot be put right, ensure instead that we never again return to those times.

Turing suffered twice-over during the episode in 1952 which was followed by his death from cyanide poisoning two years later. His crucial wartime role at the code-breaking centre of Bletchley Park could not be disclosed to anyone, including his colleagues at Manchester university where he effectively built the first modern computer.

Bletchley Park: Turing's vital wartime work there remained secret both to his colleagues and at his indecency trial. Photograph: Andy Hall/Channel 4

You can read more about his work in the Guardian Northerner's previous post on the campaign here. The website for the Alan Turing Year is here.

Professor Barry Cooper of Leeds University, a leading mathematician who is chairing the centenary celebrations said:

This is very disappointing – but we are regarding it as only an initial attempt to kick controversy into the long grass. Turing had an absolutely exceptional mind and we can only surmise what progress the UK lost through his tragic death. It would be a precedent but a welcome one, for all those lesser-known people who suffered similar disgrace and unhappiness at a time very different from our own.



Cooper said that protests were coming in from all over the world, including one from the leading American mathematician Dennis Hejhal which deplored the government's use of precedent to defend the decision. In a message to Cooper, Hejhal uses maths to good effect:



i see that the House of Lords rejected the

pardon Feb 6 on what are formal grounds. if law is X on date D, and you knowingly

break law X on date D, then you cannot be

pardoned (no matter how wrong or flawed

law X is). the real reason is OBVIOUS. they do not

want thousands of old men saying pardon us

too. i hope there is an appropriate hullabaloo

in the UK.

In his 2009 public apology, Gordon Brown said:

Thousands of people have come together to demand justice for Alan Turing and recognition of the appalling way he was treated. While Turing was dealt with under the law of the time and we can't put the clock back, his treatment was of course utterly unfair and I am pleased to have the chance to say how deeply sorry I and we all are for what happened to him. So on behalf of the British government, and all those who live freely thanks to Alan's work I am very proud to say: we're sorry, you deserved so much better.

The e-petition can be signed here.