Lib Dem manifesto at a glance: Brexit, care and regional investment

The move is a sign of defiance to the party's critics who warn that its fiercely pro-European message will not play well in their Brexit-backing heartlands.

The party has also unveiled a raft of policies to boost the country's health and care sectors, and invest in schools, transport and digital infrastructure.

This is in addition to plans to legalise cannabis and enhance the Northern devolution agenda - but the party offers no commitment to scrapping tuition fees.

Opposing a Hard Brexit forms the centre-piece of the 95-page document, with the party pledging to keep Britain "as close as possible" to the EU.

This includes a commitment to push for membership of the single market, and to a vote on the final deal with the EU, with the option of "remaining in".

The decision to place Brexit so high up the agenda comes despite concerns that many former Lib Dem supporters in pro-Leave areas like the South West will be turned-off by these policies.

It indicates a greater focus on the party's more metropolitan heartlands, such as those in London, where ousted heavyweights like Vince Cable are hoping to recapture their old seats.

Other key commitments include:

- Investing an extra £6 billion in the NHS and social care services

- £5 billion for a new British Housing and Infrastructure Development Bank,

- Creating a new ‘start-up allowance’ to help those starting a new business with their living costs in the crucial first weeks of their business.

- Reversing all cuts to front-line school and college budgets, protecting per-pupil funding in real terms

- Reinstating maintenance grants for the poorest students, ensuring that living costs are not a barrier to disadvantaged young people studying at university

- Significant investment in road and rail infrastructure, including a continued commitment to HS2, Crossrail 2 and rail electrification

- Developing a strategy to tackle childhood obesity, including restricting TV advertising before the 9pm watershed and Introducing mandatory targets on sugar reduction for food and drink producers

- Introducing a legal, regulated market for cannabis

- Championing the Northern Powerhouse and Midlands Engine initiatives, and devolving further revenue-raising and decision-making powers away from Westminster

- Reversing cuts to housing benefit for 18-21-year-olds and increasing the rates of Jobseeker’s Allowance and Universal Credit for those aged 18-24

- Helping people who cannot afford a deposit by introducing a new Rent to Own model

- Investing £2 billion in innovative solutions to ensure the provision of highspeed broadband across the rural UK

- Maintaining a minimum nuclear deterrent, but procuring three boats instead of four

These will be funded by:

- Increase in corporation tax to 20 percent (£3.6bn)

- Raising the basic, higher and additional rates of income tax by 1p (£6.3bn)

- Abolishing the marriage allowance (£2bn)

- Cracking down on tax avoidance (£2.5bn)

- Taxation on cannabis (£1bn)

- Borrowing £19bn for capital investment in schools, housing and infrastructure