Partners and children of Rover employees have taken their fight against job losses at the Longbridge car factory to the heart of London.
The children of Rover protesters go straight to the top
A convoy of coaches headed from Birmingham to Downing Street, where the families handed Tony Blair a letter.
The protesters called on Mr Blair to "pull up his socks" and renew efforts to rekindle a deal with a Chinese car company, in a bid to save 6,000 jobs.
A £6.5m government loan has prevented any redundancies being made this week.
Scores of people gathered outside Downing Street, armed with home-made banners and posters, after travelling from the stricken Longbridge factory in Birmingham.
Two children, whose father has worked at Longbridge for 16 years, held up a hand-made sign which read: "Please don't forget about us Mr Blair."
Gemma Cartwright, one of the main organisers of the protest, led a group of six women into Downing Street to hand over the letter.
The letter urged the government to help defend the lifeblood of the West Midlands, and Mrs Cartwright added that the impact of a Rover closure would hit people across the UK.
"We have come here today because we need the support from the government," she said.
"We want them to pull their socks up and get behind the Shanghai deal."
Mr Blair was not at No 10. He was in another part of the capital continuing with the election campaign.
Administrators PricewaterhouseCoopers (PwC) have continued efforts towards securing a partnership deal with the Shanghai Automotive Industry Corporation (SAIC), but said there were no signs of progress.
They also confirmed on Wednesday that they did not have the money to reimburse dealers for honouring warranties on new Rover cars.
As many as 150,000 customers could be affected.
Dealers are owed about £25m by MG Rover, much of which relates to warranty-related work they have already carried out on customers' cars.
They are unlikely to get this back as they are not thought to be near the top of any list of potential creditors.
However, PwC said most dealers would be able to advise customers on where to get alternative cover for their cars.
It is feared that unpaid bills could lead to job losses at Rover dealers.
The protest has support from all age groups
Workers have been told they will receive £280 for each year worked at the company, to a maximum of 12 years, meaning long-term employees face a capped package of just above £3,300.
Another organiser of the London protest Liz Hanks, whose husband has worked in the Longbridge paint shop for 15 years, said: "Our husbands deserve the same as other car workers, such as those at Ford in Dagenham who received between £30,000 and £40,000."
Staff at supply firms have also complained that they are the "forgotten workers" of the crisis.
Employees who have been told to go home until further notice say they are in limbo.
They say they are unable to look for other jobs or claim unemployment because they have not yet been laid off.
"We don't know if we're going to be paid. We haven't been made redundant, we haven't been laid off. What can we do?" said one worker.
On Tuesday, a PwC spokesperson was quoted as saying the UK government might extend its emergency loan to Rover if the administrators could prove there was a "sound business logic" to do so.
However, there remains a worry that continued government support could fall foul of European Union competition rules which prevent firms from receiving state aid.
Rover's difficulties have started to have a knock-on effect on its suppliers across the Midlands.
The Press Association reported that Stadco, which makes panels for MG and Rover cars, had announced plans to lay off 230 of its 450 workers at its Coventry plant.
Further jobs could be under threat at the company's Shrewsbury plant, it was reported, unless Rover can seal a deal to secure its future.
Stadco said on Tuesday that the possible demise of MG Rover would have an "inevitable" impact on its staffing levels.