Image caption Britain is alone in Europe by resisting the switch to metric

Britain's mixture of measurement systems will give this summer's Olympic visitors the impression the country is "a nation living in the imperial past", a former foreign secretary has said.

Lord Howe of Aberavon called for an urgent changeover to metric.

He told peers the lack of action to deal with the "confusing shambles" was the "most glaring omission" from the Queen's Speech.

Home office minister Lord Henley said people were yet to be convinced.

Lord Howe was a minister under Conservative prime ministers Edward Heath and Margaret Thatcher.

During a debate in the upper house, he said British weights and measures were "in a mess".

"Litres for petrol and fizzy drinks, pints for beer and milk, metres and kilometres for athletics and the Ordinance Survey, miles per gallon for cars, the metric system for school, still pounds and ounces for the market.

"This muddle does matter. It increases cost, confuses shoppers, leads to serious misunderstandings, causes accidents, confuses our children's education and, quite bluntly, puts us all to shame."

'Metrically literate elite'

A former chancellor, foreign secretary and consumer affairs minister, Lord Howe said the separate systems would confuse visitors to London during the Olympics.

Britain had been "dithering" on changing the measurement system for 150 years, he said, adding there was now a split between a "metrically literate elite and a rudderless and bewildered majority".

But government minister Lord Henley said the experience of the 'metric martyrs' - when grocer Steve Thoburn was convicted for using only imperial scales - showed the UK population was not yet convinced of the need for change.

"It is a matter where we would like to take the people with us. I'm not quite sure, if one looks at the 'metric martyrs' and others, we have quite convinced the rest of the population of the merits of proceeding in the direction you would want to go in."

Calling for a switch to metric "as swiftly and as cleanly as possible", Lord Howe added: "We simply cannot afford to go on crippling ourselves with acceptance of the present mess and it certainly would be madness to go back."

Britain remains unique in Europe as the only country to hold on to imperial weights and measures.