By James Toney in Rome

SCOTS Hannah Miley and Caitlin McClatchey helped Great Britain power to a new European record in the 4x200m freestyle relay at the World Swimming Championships here today.

Only Jo Jackson was rested for this morning's heat at the Foro Italico, but she'll be back to join McClatchey, Miley and Rebecca Adlington in tonight's final, at the expense of youngster Jazmin Carlin.

At last year's Beijing Olympics, Britain rested all their big names in the heats and failed to make the final - leaving double Commonwealth champion McClatchey devastated.

But this time they got their tactics spot-on as the quartet, anchored by double Olympic champion Adlington, touched home in 7.49.04, carving more than three seconds off the previous British record.

And tonight they believe they can go even quicker as they look to become the first British relay world champions since 2001.

"It was just amazing to be part of the team - I am still quite surprised really," said medley specialist Miley, who pulled out of this morning's 200m breaststroke to focus on the relay.

"And to perform so well - setting a new British record and a Championship record on our first swim together was really promising."

Scot Kris Gilchrist was ninth quickest into tonight's 200m breaststroke semi-finals in a personal best 2.09.31.

The championship record was rewritten five times during the heats with American Eric Shanteau fastest in 2.08.55 "I am really pleased with that," said Gilchrist. British Gas and British Swimming. The nation's leading energy supplier, British Gas, is the Principal Partner of British Swimming, supporting the sport at all levels: 'From paddling pool to podium'. For more information visit www.britishgas.co.uk/swimming