The world class tests, due to be piloted in the autumn, will seek to measure the ability of the top 10% of pupils at maths and science in schools in disadvantaged areas.

Estelle Morris wants closer links between the US and UK education departments

It is intended that this will allow an objective "calibration" of pupils' ability, set against the most able pupils in industrialised countries around the world.

This would refine the "Timss" system - an international maths and science survey - currently used to compare levels of academic achievement in maths and science in 40 countries.

Richard Riley said that he would be interested in finding ways to compare large, urban school districts in the United States, with schools facing similar challenges in the United Kingdom.

The US education secretary was in the UK to promote joint efforts to tackle underachieving schools - which will include a school improvement conference in the United States in October.

Building links

Emphasising the need for education systems to set up international links and develop common strategies, Richard Riley said that sharing such information would be a "win-win" exchange.

Among the lessons that he believed could be learned from the United Kingdom had been the success of the national curriculum in improving maths, science and information technology.

Describing the curriculum in the United States as "a mile wide and an inch deep", Richard Riley said that the US had found itself lagging behind countries with a more focused curriculum.

Estelle Morris also looked forward to a closer relationship with the United States education department, saying that they had common concerns in areas such as turning around failing schools and finding ways of overcoming economic disadvantage.

Both education departments have proposed class size reductions, identified problems with "failing" schools, extended after-school provision and sought to tackle crumbling school buildings.

"We have worked assiduously at building links with the education system in the United States," said Estelle Morris. And she praised the readiness of those working in the US schools system to accept change.