LONDON — Crossrail, the largest infrastructure project in Europe, which will provide a new link across London, has reached the half-way stage, the company behind it said at a high-profile event attended by Britain's Prime Minister David Cameron. The 15 billion pound ($25 billion) project, due to open in 2018, will connect Heathrow airport west of London to the county of Essex in the east through 42 km of new tunnels in a bid to speed up connections and relieve pressure on London's crowded underground. The project is running on time and on budget, confirmed Crossrail on Thursday, as it hosted Cameron and London Mayor Boris Johnson at its Tottenham Court Road site in central London, 25 meters underground. “There was a time when some said that building a huge tunnel deep below the streets of London was a mad plan that would do nothing for our economy. But as this awe-inspiring project hits its halfway point we can see how wrong the naysayers were,” Johnson said. Crossrail will add 10 percent more capacity to London's rail network and help cope with the city's forecast population growth to 10 million people in 2030 from 8.4 million now, Cameron said. Around 10,000 people currently work on Crossrail and the project is supporting 55,000 jobs around the country during its construction. Work began in 2009 and digging the new tunnels has uncovered a range of archeological finds including 20 Roman skulls and a graveyard which could hold the remains of some 50,000 people killed by the plague more than 650 years ago. Crossrail is a subsidiary company of Transport for London (TfL), a public authority partly funded by the government's Department for Transport. British construction firms Balfour Beatty, Costain and Laing O'Rourke are all involved in the project. — Reuters