Complaints about the offensive phone calls made by Jonathan Ross and Russell Brand to veteran actor Andrew Sachs last night topped the 10,000 mark, the BBC said.

Complaints about the offensive phone calls made by Jonathan Ross and Russell Brand to veteran actor Andrew Sachs last night topped the 10,000 mark, the BBC said.

Last night, Prime Minister Gordon Brown condemned the pair, saying: "This is clearly inappropriate and unacceptable behaviour, as is now widely recognised.

"Ofcom have said they will investigate the matter and it is for the BBC, the BBC Trust and Ofcom to take any appropriate action."

The complaints, made about Brand's Radio 2 show, involved a claim that the comedian had slept with the Fawlty Towers actor's granddaughter Georgina Baillie, 23.

The presenters also joked the actor might kill himself in the pre-recorded show - which was cleared to air despite the actor, who played Manuel, being upset. The media watchdog Ofcom yesterday confirmed an investigation would be launched.

Ross, 47, issued a personal apology accompanied by flowers.

Brand, 33, is understood to be following suit, although Sachs reportedly said he is yet to receive a direct apology.

Sachs, 78, told the BBC: "I have not seen or spoken to Georgina yet. She's very upset at having put her family through this and she feels very guilty." As to seeing Georgina in the newspapers, he said: "I do not like it, would you? But it's her life and I just let her get on with it.

"Jonathan Ross has personally delivered a letter of apology and some flowers.

"He made no excuses and was very frank and open. He's in a lot of trouble and I don't want to pile any more on him.

"My granddaughter hasn't heard from either Ross or Brand and I do think they owe her an apology."

The BBC has also apologised and promised a full investigation into how the situation happened.

Tim Davie, director of audio and music at the BBC, admitted the programme that went out was "unacceptable".

In an interview with the BBC, he said: "We are going to have a full investigation, look at the factors and decide the appropriate action."

He said it was too early to say what exactly happened and to apportion blame at this stage would be the wrong thing to do.

Asked if anyone would "take the rap" he said the key action was to produce a balanced report, adding: "It's too early to speculate what those decisions will be."

Yesterday politicians from across the spectrum waded into the row calling for BBC director-general Mark Thompson to act and the presenters to be sacked.

Culture Secretary Andy Burnham welcomed the BBC's investigation and apology "for what it now acknowledges was unacceptable".

He said the BBC Trust and Ofcom "will now have to look at how and why such a serious breach of broadcasting standards happened".

Mr Burnham added: "I, and I think the public, expect these inquiries to be carried out thoroughly and as a matter of urgency." Conservative leader David Cameron said: "I think the BBC have got some very straightforward questions to answer. The main question is why did they allow this programme to be broadcast, given that it was pre-recorded?

"So we need to know who made the decision to broadcast it? How high up the editorial chain did it go? Who examined it? Why did they conclude that it should be broadcast?"

Yesterday a newspaper reported that a young producer was given the responsibility of calling Sachs to check if he would be happy for the messages to go out. But a source also said that an un-named senior editorial figure gave the broadcast the go-ahead. Sachs's agent Meg Poole formally complained to the BBC about the calls.

Justice Minister David Hanson said he did not think the DJs' behaviour was "appropriate" or "in keeping with broadcasting".

Labour MP Andrew Mackinlay and Tory MP Nigel Evans tabled a parliamentary motion saying the behaviour of Brand and Ross was "base and vulgar", "diminishes the reputation of the BBC and should not be funded by the licence fee".

Tory MP Nadine Dorries called for the BBC to end its contracts with Brand and Ross. She said: "At a time when hard-pressed families are feeling the strain on their household budgets, many people will feel annoyed that the BBC licence fee of nearly £140 a year is being misused in this way."

The BBC Trust has asked for a report from BBC management on its investigations.