The Commission for Racial Equality says it does not want to pressure MPs into signing its anti-racism election pledge.

The pact was drawn up to encourage politicians not to use racist language during the forthcoming general election campaign.

On Friday, the Shadow Chancellor, Michael Portillo became the most senior Conservative to refuse to sign the CRE's code of conduct.

One Tory backbencher has said the commission's action reminded him of the anti-communist witch-hunts in the United States in the 1950s.

I went into public life to speak for myself and I will use my own language, my own words

Michael Portillo

But the commission's Vicki Kennedy said there had been no intention to make MPs feel pressured into signing the document, and they were free to publish their reasons for not doing so on the CRE website.

The CRE had merely acted as a "mediator" between the parties in drawing up the pact, and the pressure to sign had come largely from opposition politicians and the media, she said.

But the commission has also stressed that the pact should not deter politicians from "robustly debating" sensitive issues such as asylum and immigration.

Some 78% of Labour MPs, 100% of Liberal Democrats and 35% of Conservatives have so far signed the compact.

'Offensive'

Labour has said that all its MPs will be expected to sign.

But the pact has attracted increasing criticism, with some other Tory MPs rejecting it and a former minister calling it "loathsome and offensive".

Conservative Party chairman Michael Ancram insists it was clear from the start party leader William Hague had signed the compact on behalf of the whole party.

Ancram: Warned candidates on racism

Asked about it during a trip to Wales on Friday Mr Portillo said: "No, I haven't signed it because I speak for myself and I have said that I offer equality of esteem to everyone in this country.

"I don't like signing bits of paper and questionnaires thrust in front of me.

"I went into public life to speak for myself and I will use my own language, my own words."

The CRE pledge

Labour: 269 of 417 MPs signed Tory: 55 of 160 signed, 4 refused Lib Dem: 45 of 47 signed Others: 9 signed

Mr Portillo's comments have dramatically increased the tempo in the debate on racism in politics - and could be seen as an embarrassment to Mr Hague.

The pact commits politicians "not to pitch one group against another for short term political or personal gain".

And it commits the main party leaders - who all signed it - to taking action against any candidates or campaigners who provoke racial prejudice.

Liberal Democrat leader Charles Kennedy said on Saturday that the Tories were "self-destructing" over the race issue, and that Mr Hague was attempting to kindle fears over immigration and asylum.

He said: "Mr Hague says that Britain is turning into 'a foreign land' and that we are becoming over-run with 'bogus asylum seekers'.

"In using language like this, the Conservative leader has fostered a climate in his party where racist sentiment can be given voice."

Mr Kennedy also commented on Mr Portillo's decision not to sign the CRE's pact, saying it "owes more to his Conservative leadership aspirations than it does to a decent and sensible debate about asylum and immigration".