It's musical chairs at No. 10 as Harman, Darling and Straw deputise as PM... but holidaying Gordon says he's still in charge

As the first woman to be in charge of the country since Margaret Thatcher, perhaps some of the Iron Lady's formidable nature had rubbed off.

For Harriet Harman wasted no time in stepping into Gordon Brown's shoes yesterday as she made herself at home in Number 10 and as top dog while he is on holiday.

Already rumoured to have issued a series of demands to Downing Street officials, she lined up a set of meetings with colleagues and reportedly even invited her family round for a guided tour.

The Prime Minister, however, has not been branded a 'control freak' for nothing - and carefully made it clear once again that he has not relinquished his hold on the reins of power.

While Miss Harman, Labour's deputy leader, reportedly told friends it was a 'great privilege' to be in the chair, Mr Brown's spokesman insisted he was still in charge.

And he also stressed she was merely one of several senior ministers still in the capital on hand during the PM's break in Suffolk with his family.

'The Prime Minister remains in charge whenever he is on holiday. In the normal way, there are senior ministers in London to deal with the business of government,' the spokesman said.

'Harriet Harman is one of those ministers who are available. She is available to deal with the day-to-day business of government. The Prime Minister remains in charge.'

In charge: The Prime Minister's spokesman insists he is still in control despite being on holiday

Number 10 initially briefed that Chancellor Alistair Darling and Justice Secretary Jack Straw would stand in for Mr Brown and made no mention of the Minister for Women.

Despite winning the deputy leadership last year, Miss Harman was never given the title of deputy prime minister, meaning she was not the automatic replacement.

Adding to the confusion, Mr Darling was heard at a reception last week joking that he would soon 'have his finger on the nuclear button'.

It emerged later, however, that Miss Harman would be stepping in after all - becoming the first woman to take the helm since Mrs Thatcher in 1990.

Stand-ins: Jack Straw (left) and Alistair Darling are also on hand to help out

Before she even arrived in Downing Street yesterday, the Peckham MP's demands were said to have riled officials.

She has asked to be called every night at 10.30pm by a press officer to run through the first editions of the next day's newspapers.

The minister also asked for her private secretary and special advisors to be included in a 7.30am conference call followed by a 9am meeting around the Cabinet table.

There is increasing speculation she could be preparing to throw her hat into the ring if Mr Brown steps down from the Labour leadership.

Aides to the Prime Minister briefed that she would not be standing in for him at PMQs or at Number 10 when she became deputy leader.

But since then, she has appeared twice at the weekly Commons' session and has even surprised the Tories with her dogged performances.

Mr Brown, meanwhile, has presided over a slump in the polls and seen his personal authority diminish in the face of defeat after defeat in local and by-elections.

Because he is also going to the Beijing Olympics, he will be away until the end of August - allowing plenty of time for his rivals to consider their position.