Speed limits on motorways and national main roads are to go up, under new proposals being considered by the Government. All limits will also be set in kilometres per hour.

Under the move the general limit on main roads to will rise to 62 mph, or 100 kilometres per hour. The speed limit on motorways is to rise from 70mph to 75mph or 120 kilometres per hour.

But limits near schools and in built up areas will fall to under 20mph, and the limit on non-national roads around the country will fall from 60mph to 49mph or 80 kilometres per hour.

It is expected new km per hour signage, accompanied by a major advertising campaign, will all be in place by September next year.