Crossrail has announced the first of its tunnels has been constructed.

The development marks progress on the project, which has drilled 13 miles of its total 26-mile network.

Its first tunnel was finished when the tunnelling machine completed the 4.2 mile trip to Farringdon from Royal Oak.

Crossrail programme director Andy Mitchell said: "Crossrail's construction continues to move ahead at a significant pace.

"A further six tunnelling machines are currently hard at work constructing over 100 metres of new tunnel each day with major tunnelling due to complete next year."

This week also saw the last of the concrete rings cast at Crossrail's segment factory. These rings are used by the boring machines to line the routes as it digs them.

In September, it was announced one million tonnes of earth had been dug through the company's operations.

Crossrail is expected to open in 2018, offering faster train times and ten per cent extra capacity along London and the south-east. More than 200 million passengers are expected to travel through it annually.