Construction on Crossrail is due to start in 2010

The �16bn rail link will connect Maidenhead, Berkshire, to Essex through London and will to add �20bn to the UK's economy and generate 30,000 jobs.

Since the project was announced in 1990, it faced obstacles over funding.

Touted to be Europe's largest civil engineering project, it was stalled for years due to a shortfall of �400m.

That gap was recently met by the City of London Corporation, and Prime Minister Gordon Brown gave the green light on Friday.

Crossrail gets green signal

The Crossrail was initially proposed in 1989, when Margaret Thatcher was prime minister, and it was formally announced by the then Transport Secretary, Cecil Parkinson, in 1990.

The rail will link to both mainline and underground, and will increase the total capacity of the city by 10%, easing the pressure on existing train lines.

Every hour during peak times 24 crossrail trains will criss-cross through central London carrying an additional 72,000 people.

The line will be about 73 miles long, stopping at 38 stations, with about 25 miles of the tracks taking commuters through tunnels.

'Lasting legacy'

The bulk of the construction will involve digging two 10-mile tunnels deep under central London between Paddington and Stratford stations.

The Maidenhead to Shenfield rail link will divert in the west to Heathrow airport and go to Abbey Wood, passing through the Isle of Dogs in the south.

The Crossrail Bill, which is still in Parliament, is expected to receive Royal Assent by 2008.

The rail link is seen as being more than another addition to the city's transport infrastructure. Transport Secretary Ruth Kelly said it would give "a lasting transport legacy to London for centuries to come".

After nearly 20 years, it may be that Crossrail joins the other major cross-capital route, Thameslink, in finally achieving financing.

High-speed link Planned operational date 2015 From Maidenhead and Heathrow in west From Shenfield and Abbey Wood in east Through central London tunnels New stations at Paddington, Bond Street, Tottenham Court Road, Farringdon, Liverpool Street, Whitechapel and Canary Wharf