Some members of a House of Commons committee have demanded that she should appear before it to explain when she knew of allegations about the breach of an arms embargo by the British firm Sandline International.
In response to a question from the Conservative leader, William Hague, the Prime Minister said there was "not a shred of evidence" that she or any other minister had misled Parliament over the affair.
There has been continuing controversy over when ministers knew Customs and Excise was investigating a breach of the embargo on Sierra Leone by Sandline International. Baroness Symons told the House of Lords on 11 March that she knew only what she had read in the newspapers, but the Foreign Office permanent secretary told the Foreign Affairs Committee that she had been briefed by officials before she spoke.
At Prime Minister's Questions, Mr Hague said the minister should resign. The Foreign Secretary, Robin Cook, had repeatedly told MPs that no minister knew about the investigation before mid-April, he said.
"Isn't it absolutely clear from the committee yesterday that at least one minister was informed in early March. So did the foreign minister fail to tell the Foreign Secretary, or did the Foreign Secretary fail to tell this House?" he asked.
Mr Blair said he had not asked Lady Symons to resign.
"There is no evidence whatever that she deliberately misled either the House of Lords or indeed anybody else," he said.
"From what I've seen there is no evidence - indeed there is not a shred of evidence - that any ministers have deliberately misled anybody; or that the original allegation, which is that they conspired in some great conspiracy to give arms in breach of a UN arms embargo, there is not a shred of evidence to support that. There never has been."
Today, the committee will meet to discuss outstanding business, but some of its members say they will ask for Baroness Symons to be called.
Its chairman, Donald Anderson, said yesterday morning in a radio interview that it was likely the baroness would be called. But later in the day he said he believed that she might resolve the issue herself when she returned from a trip to Canada.
"Somebody has got it wrong, there is a conflict which is capable of resolution and if politicians or even senior civil servants say they have got it wrong, people tend to be forgiving," he said.
"If I were her private office I would advise her to clear it up, and swiftly."
David Wilshire, a committee member and Conservative MP for Spelthorne, said he was tabling a new series of parliamentary questions on the affair.
David Heath, the Liberal Democrat member of the committee and MP for Somerton and Frome, said it would continue to demand the facts of the case.
The Foreign Office has recently refused to give information on the grounds that Sir Thomas Legg is conducting a separate inquiry.
"I am at a loss to understand the tactics of the Foreign Office at the moment," he said.Reuse content