ON the first-ever World Twins Day today, James and Oliver Markham-Bradley will definitely be celebrating.

The 22-month-old pair can be more than double trouble, according to mum Jane Cunningham, but the Easingwold family will still be joining in the fun.

Jane, 36, said: "I am sure I can think of something to celebrate. We're always busy doing things so it won't be hard to think of something."

The brothers were pictured at Smartypants Nursery in Castlegate, York, which they have attended since they were three months old.

Hundreds of twins of all ages were attending a lunchtime party today to mark the special day.

The likelihood of being a twin has increased with the spread of fertility treatments, which now account for 25 per cent of twin births.

Experts at St Thomas Hospital were hosting the event in a marquee on the south bank of the Thames in London.

Nearly 10,000 multiple births were recorded last year in the UK, and one in 35 children is now born as a twin, while triplet births have quadrupled in many countries. Among guests at the party were American obstetrician Louis Keith and his identical twin brother Donald.

Updated: 11:49 Tuesday, July 03, 2001