Gordon Brown signalled a new push for agreement on safeguards surrounding an increase in the maximum detention time of 28 days for terrorist suspects yesterday after his Security Minister staged an embarrassing 65-minute retreat over whether such an extension was even needed.

Admiral Lord West of Spithead, one of the non-politicians brought into the Prime Minister’s “Government of all the talents”, called himself a “simple sailor” after tripping himself up in an interview on the BBC Radio 4 Today programme.

Even though Mr Brown, Jacqui Smith, the Home Secretary, and other ministers have been urging an increase in the 28-day limit, Lord West stunned listeners within the government machine by stating that he still needed “to be fully convinced that we absolutely need more than 28 days”.

A slightly incredulous interviewer pushed him and he insisted: “I want to be totally convinced because I am not going to go out and push for something that actually affects the liberty of the individual unless there is a real necessity for it.”

Within minutes the news bulletins were leading with stories of a split in the Government.

Lord West heard one of them as he travelled to No 10 for a meeting with his boss and security experts in preparation for yesterday’s statement. The situation was complicated because previously he had said that he favoured increasing the limit.

The word from Whitehall yesterday was that Lord West had decided that he needed to clarify his words, but whether he was pushed into doing this by Mr Brown no one was willing to say.

After his meeting with Mr Brown he emerged to tell reporters: “My feeling is, yes, we need more than 28 days.”

Mr Brown’s spokesman confirmed: “Lord West set out his position clearly in the second statement.”

Later Lord West insisted that he had not changed his mind, but that as a “simple sailor” he had not chosen his words well. But his gaffe was a godsend to opposition parties on the day that Mr Brown set out a fresh raft of counter-terrorism measures. It also upset senior police officers, such as Sir Ian Blair, the London commissioner, who has been calling for the increase.

David Cameron seized on it as he responded to the Prime Minister’s statement on national security in the Commons, saying it appeared Lord West had been leant on since his interview earlier in the morning. “Won’t this episode confirm in some people’s minds that, when it comes to this vital and important debate, the Government is not concerned so much with the evidence as the politics?” he said.

Nick Clegg, the Liberal Democrats’ home affairs spokesman, highlighted the “pitiful spectacle” of a minister saying one thing at ten minutes past eight and the exact opposite an hour later after a meeting with the Prime Minister. Mr Brown dealt with it by quoting remarks from Lord West on earlier occasions when he had backed an increase in the limit.

He told Mr Cameron: “As you well know, Lord West today has also said that he favours going beyond 28 days.”

Even so, Mr Brown adopted a conciliatory approach, saying parties should try to reach a consensus on the safeguards that could be adopted in rare cases where it was necessary to exceed the current 28-day limit. He told Vince Cable, the acting leader of the Liberal Democrats, that this could include cases being referred to a judge, the involvement of the Director of Public Prosecutions, a report to the Commons and a study by the independent reviewer of terrorism laws.

He said: “Our ability to defend our liberties faced with a terrorist threat is something that is absolutely crucial to both the message we send to ourselves about the health of our society but also the message we send round the world that we will not be blown apart by terrorist activity in our country and we will not give in to it.”

Ministers are counting on divisions in Conservative ranks to help them to push through a higher limit.

Patrick Mercer, the Tory MP for Newark, who contributed to Lord West’s report, said he agreed with the need to achieve consensus but cautioned: “The fact remains that if we do go beyond 28 days our enemies will brand this as internment.”

Lord West’s gaffe was not the first by one of Mr Brown’s “Government of all the talents”. Lord Malloch-Brown, the former UN diplomat appointed to become Africa minister caused ripples when he suggested that Britain and the United States would not be “joined at the hip”. And Lord Jones of Birmingham – the former CBI Director-General – said that companies viewed the recent capital gains tax changes as “terrible”.

Time for a change

Admiral Lord West of Spithead on BBC Radio 4 Today programme:

08.13: "The first thing I want to say is that I need to have absolute evidence that we need longer than 28 days."

Sarah Montague: "You're not convinced?"

Lord West: "I want to be totally convinced because I'm not going to go and push for something that actually affects the liberty of the individual unless there's a real necessity for it."

08.13: Lord West: "I still need to be fully convinced that we absolutely need more than 28 days and I also need to be convinced what is the best of doing it."

08.14: "I want to be completely convinced about this because it's a very important issue."

Lord West, emerging from a security meeting at 10 Downing Street:

09.15: "My feeling is, yes, we need more than 28 days. I personally absolutely believe that within the next two to three years, we will require more than that for one of these complex plots. So I am convinced that's the case, but it is very difficult because there is a civil liberties issue."

Lord West clarification statement issued by Home Office:

09.49: "I am quite clear that the greater complexities of terrorist plots will mean that we will need the power to detain certain individuals for more than 28 days . . .

"I am convinced that we need to legislate now so that we have the necessary powers when we need them. The Government would be failing in its responsibility to protect national security if we waited until we needed more than 28 days to act."

Lord West at Arsenal stadium:

10.30: "As a simple sailor rather than a politician . . . maybe my choice of words wasn't very clever."

Prime Minister's spokesman:

11.39: "I think Lord West's statement speaks for itself. I think he thought it was necessary to make sure his position was properly understood.

"I'm not sure he has changed his mind. Lord West made his position quite clear. Lord West gave his views quite clearly in his second statement."

Life on the ocean wave

1965 joined the Royal Navy

1978 qualified as an advanced warfare officer

1982 commanding officer of HMS Ardent, right, a frigate sunk by Argentine bombers in the Falklands conflict, with the loss of 22 men. Awarded the Distinguished Service Cross for courageous leadership

1985 reprimanded after losing classified papers while walking his dog on a towpath. They were found and passed to a Sunday newspaper

1996 as a rear-admiral, appointed Commander UK Task Group, an operational force

1997 switched role to Chief of Defence Intelligence

2001 appointed Commander-in-Chief Fleet.

2002 promoted to First Sea Lord and Chief of Naval Staff

2006 retired from the Navy.

2007 appointed Security Minister in Gordon Brown’s “government of all the talents”

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