Thousands of female engineers will be trained up as part of a 'national mission' to get Britain building again, Ed Miliband announced today.

The Labour leader said it was a 'national embarrassment' that just one in 25 engineers were women.

He pledged to ensure an extra 400,000 engineers were trained up by 2020 - with a Labour source promising a 'significant increase' in the proportion of women.

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Labour leader Ed Miliband was given a tour of the Tottenham Court Road Crossrail site in London today

Mr Miliband said the engineers were needed to meet a shortfall in the number of skilled workers in the economy.

He announced his plan during a visit to the Crossrail construction site in central London, which he said was an 'inspiring' project which should encourage the next generation of engineers.

After another bruising period for his leadership, with the departure of Emily Thornberry from his shadow cabinet following her controversial tweeted image of a house flying three St George flags with a white van parked outside, Mr Miliband sought to shift the focus to his plans to rebalance the economy.

After donning a hard hat and high-visibility safety gear for a tour of the works near Tottenham Court Road station, the Labour leader said: 'I think this is an inspiring place to be.

'Our country faces a shortage of 400,000 skilled engineers if we don't act. That's why it's the mission of the next Labour government to put that right.

'It's the way we will create good jobs at decent wages and it's also the way that we are going to create a recovery that doesn't just work for a few people at the top but actually works for working people.'

Mr Miliband said Britain was facing a shortfall of some 400,000 engineers by 2020 if there was not a major recruitment drive

The Labour leader said the Government had failed to act to 'get the skilled engineers we need' to stop British industry being reliant on foreign workers

Mr Miliband acknowledged that the problem had existed for a number of years.

'Over a long period we haven't taken the action necessary to get the skilled engineers we need,' he said.

'That's about inspiring our young people in schools and colleges and creating new gold-standard technical qualifications for them in engineering.

'And it's about apprenticeships for the next generation. It's about saying to companies 'if you want a major government contract you must provide apprenticeships, if you bring in a skilled worker from outside the European Union you must also provide apprenticeships for the next generation'.

'It's that kind of national mission, of government and business together, that will create the skilled jobs and the skilled engineers we need.'

Writing on Facebook he said there was a choice between 'two different directions' for the country.

One was through the creation of skilled workers, such as those working on the major transport project in London, while the other involved 'cowboy recruitment agencies, operating in the shadows of the economy, exploiting workers, undercutting wages and undermining conditions'.

He said: 'Only a Labour government will have the values, approach and ideas to turn the economy we have with low wage, low-skilled jobs into the economy we need, with high-skilled, high wage jobs.'

Mr Miliband's pledge to boost female engineering comes after another tough week following the sacking of Labour MP Emily Thornberry

Mr Miliband said the UK had to 're-establish our historic reputation as a world leader in technology and manufacturing'.

Labour said industry estimates were that an extra 780,000 more engineers would be needed between now and 2020, but current projections were for only around half of that number to be trained, leaving a shortfall of some 400,000.

Mr Miliband said: 'This is not just a shortage of the traditional civil, mechanical and electrical engineers, but also in information technology, green energy, and life sciences where many of the jobs of the future will be created.

'And we need to ensure Britain does not waste the talents of any our young people, be they men or women.

'It should be matter of national embarrassment that the UK has the lowest proportion of female engineering professionals of anywhere in Europe.'

In 2013, just 14% of engineering graduates were women, and females made up only 4% of all professionally-registered engineers.

Mr Miliband said: 'We will work with schools to ensure more young people, girls as well as boys, do Stem subjects - Science, Technology, Engineering and Maths - to nurture this new generation.

'We will work with young people themselves, encouraging and inspiring them at every stage, with a clear vocational route through education into an engineering career that is desperately needed now.

'And we will work with industry to put employers in charge of the money for training young people so that as many school-leavers go into a high quality apprenticeship as currently go to university.

'This is the kind of future we can build together, doubling the rate of engineers being trained here by 2020 rather than importing them from abroad or leaving businesses without the skills they need to succeed.'

As well as encouraging engineers, Mr Miliband said Labour would not tolerate a 'world of work that is becoming more brutal because of the way some rogue employment agencies have been allowed to operate'.

He said: 'We will close the legal loophole which allows some to undercut the wages of permanent staff.

'We will stop them from recruiting exclusively from abroad.

'And we will serve notice on the rogue agencies that they must clean up their act.'