Work to update a major stretch of the M20 so it can cope with more cars is expected to start in two years.

Highways England, which will replace the Highways Agency from Wednesday, wants to add an extra 11 miles of carriageway between junction 5 for Aylesford and 3 for Borough Green.

It is expected to be complete by the 2019-20 financial year and once finished it will be what the government calls a smart motorway.

This is a stretch of road that can increase its capacity by using variable speed limits and running vehicles on the hard shoulder if it is congested.

Plans for the project are still in their infancy and a highways spokesman was unable to say whether this would involve creating an extra 11 miles of carriageway.

Road campaigner Ian Taylor, from the Alliance of British Drivers, warned the scheme should not be done on the cheap.

He said: “If it means genuine improvement then I am all for it.

“If they are going to take away miles and miles of hard shoulder then I have my reservations. I am not saying they shouldn’t do it a little bit but hard shoulders are there for a reason.

“Widening on the cheap gives you trouble.

“Smart motorways usually mean more speed cameras. Lots of people have been caught out by them and they often have reduced speed limits for no reason.”

Money will come from an £11bn pot which will be shared nationally and a delivery plan, published today confirmed the cash has been allocated.

It is one of 112 major improvements proposed and forecasts predict that for every £1 invested there will be a £4 benefit for the economy.