The Channel Tunnel is to be extended for the first time since it opened 22 years ago with a 600metre covered section being built near Calais to stop migrants stowing away on trains to Britain.

The £4.7million project will see the tunnel encased in concrete for a third of a mile from the opening in Coquelles near Calais to the Eurotunnel terminal, where lorries and cars are loaded on to trains.

It is hoped the move will protect the line at the point where it has been repeatedly stormed by migrants. This section is currently only protected by a four-metre fence.

The £4.7million project will see the tunnel encased in concrete for a third of a mile from the opening in Coquelles near Calais to the Eurotunnel terminal, where lorries and cars are loaded on to trains (pictured)

Jacques Gounon, chief executive of Eurotunnel, told The Times: 'The risk this summer is that we will see migrants overwhelming Europe.

'I would like to not be reactive, like last July, but to anticipate the problem and have additional security measures.'

He said more security was needed to stop the migrants but fears there is a danger ministers might 'say there is no migrant issues so there is no reason to fund some additional protection'.

Work to extend the Channel Tunnel could be carried out over a four month period and would see signalling, firefighting equipment and emergency exits all introduced at various points.

Mr Gouon said another measure to protect the tunnel was also in the pipeline, with a joint control and command centre staffed with officials from France and the UK being set up in the coming months.

The taxpayer faces having to pay up to £22million in compensation to Eurotunnel for disruption caused by last summer's migrant chaos.

The firm has asked both the British and French governments to reimburse it for lost trade after thousands of migrants stormed the tunnel in July and August.

Pictured, where the proposed 600m concrete tunnel extension will be laid. Eurotunnel bosses said the section will be an example of them being proactive rather than 'reactive' in the midst of the migrant crisis

It is hoped the £4.7million project will protect the line at the point in Coquelles near Calais where it has been repeatedly stormed by migrants (pictured). This section is currently only protected by a four-metre fence

The operator faced heavy disruption as migrants from the Jungle camp in Calais repeatedly tried to enter Britain. It has applied to its regulator the Intergovernmental Commission for the payout.

The French and British government have responsibility for border control and security and in 2000 Eurotunnel successfully claimed around £13million for disruption. The latest claim would probably be split between the two countries.

The Channel Tunnel was opened in May 1994 and runs the 31.4miles between Folkestone in Kent and Coquelles, near Calais, France.