A former Soviet spy has given his professional endorsement to the appointment of John Scarlett as head of the MI6 security service.
John Scarlett gets the backing of a former Soviet intelligence officer
KGB defector Oleg Gordievsky said that no other candidate could match Mr Scarlett's experience and ability.
Mr Gordievsky dismissed criticism of Mr Scarlett's appointment because of his role in the dossier on Iraq's weapons of mass destruction.
"The Hutton Inquiry was a small episode in his life and his career," he said.
"He has got an experience that is incomparable with anyone else," said Mr Gordievsky, speaking on BBC Radio 4's Today programme.
"He is the person who is the most suitable candidate to become head of MI6. It has nothing to do with small political points connected to the Hutton Inquiry," he said.
But Mr Scarlett's appointment has been challenged by the Conservatives as "inappropriate" and "highly controversial" by the Liberal Democrats.
They have queried the selection of Mr Scarlett, currently Joint Intelligence Committee chairman, when he might still face questions from the Butler inquiry into the use of intelligence in the run-up to the war in Iraq.
The appointment was also attacked by former Labour defence minister, Peter Kilfoyle, who said he was "utterly perplexed" by the decision.
"This was a man whose role in the dodgy dossier was emphasised in the Hutton Report," said Mr Kilfoyle.
Lord King, a former Conservative defence secretary, said that the appointment should have been postponed until the Butler inquiry had been completed.
But he said that Mr Scarlett should not be blamed for any apparent closeness to the government, because of his part in the Hutton Inquiry.
"It's not the fault of John Scarlett, he was put in a very difficult position ... the relationship with the spin doctors of Number 10 has caused him some very unfortunate headlines today," said Lord King.
Prime Minister Tony Blair has already mounted a robust defence of the appointment.
Speaking on Thursday, Mr Blair said it would be "unfortunate" if the issue became politicised and stressed it had been made by an "independent panel".
What does MI6 do?
Primarily concerned with information gathering outside UK
Established in 1912 its full name was Military Intelligence, section six
For many years it did not officially exist so ministers did not have to answer questions on it
John Major changed its status so it became official
During the Cold War MI6 was primarily concerned with the USSR and its allies
Its role is primarily to gather information to aid the government's security, defence, foreign and economic policies
"You can only imagine what you guys [journalists] would have been saying to me if I had interfered with that process," he told a news conference.
"[Mr Scarlett] is someone who is a fine public servant who served both Labour and Conservative governments over many, many years and I think it's very unfortunate if it becomes a matter of political comment."
Mr Scarlett, who will be the first head of MI6 to be pictured in the media, succeeds Sir Richard Dearlove who is becoming Master at Pembroke College, Cambridge.
His appointment, by Foreign Secretary Jack Straw, came after a recommendation by a selection panel chaired by the prime minister's security and intelligence co-ordinator Sir David Omand.
Mr Scarlett's career saw him holding a succession of operational postings both in the UK and overseas.
That included being head of SIS's station in Moscow.
The Russian and French-speaker left Magdalen College, Oxford in 1970 having taken a first in modern history and has spent his entire career in MI6.
He is married with three daughters and one son.
Like his predecessors, Mr Scarlett will not give interviews or make public appearances.