Joanne Jackson lost her 400 metres freestyle world record on Saturday afternoon when Italian Federica Pellegrini reclaimed the mark at the Mediterranean Games in Pescara.

Pellegrini, the Olympic 200m freestyle champion, completely dominated her race and touched in four minutes 00.41 seconds to lower Jackson's mark set in March this year by 0.25secs, subject to ratification.

Pellegrini had previously held the record before the Loughborough swimmer eclipsed it by almost a second in Sheffield with Olympic champion Rebecca Adlington also ducking under the old mark.

It sets up a fascinating race at the World Championships in Rome next month with both British women showing top form at this weekend's British Gas Scottish National Championships in Glasgow.

Although Adlington has yet to confirm her place over eight lengths in Rome, it is inconceivable the 20-year-old will not race in the event.