It is also vital to the continuing success of London's economy linking many of the capital's economic powerhouses – Heathrow Airport, the West End and City of London, Canary Wharf and the Thames Gateway.
The engineering challenges are formidable, but the Crossrail team, ably led by Doug Oakervee, has demonstrated its feasibility and long-term economic benefits. The funding formula that has now been put in place rests on four main financial pillars – fare box revenues, government grant, direct contributions from businesses along the route and a supplementary business rate applying to all London businesses with a rateable value over £50,000.
Those of us who have championed Crossrail over the years have had to fight dogged campaigns to get where we are today.
In south east London we faced a real setback three years ago when, in an effort to reduce the then burgeoning costs of the scheme, the government unexpectedly dropped the planned Woolwich Station that would have brought huge regeneration benefits to one of London's most disadvantaged areas.
That decision was reversed earlier this year as a consequence of hard campaigning and a financial contribution from the businesses likely to benefit in Woolwich.
However, even as recently as last month there were worrying suggestions that the south east London branch from Canary Wharf to Woolwich and Abbey Wood may be deferred by three years from the planned 2017 completion date.
Mercifully that threat has receded so we can now look forward to the whole Crossrail scheme receiving parliamentary approval next summer.
Nick Raynsford is MP for Greenwich & Woolwich