While in the station, don't refrain from alliteration

Yoko Ono is to judge the world's first interactive poetry competition, which starts in London tomorrow. Commuters arriving at the capital's King's Cross station will be invited to submit haiku-style poems on the subject of the British summer from their mobile phones, using Twitter, the free social blogging site.

The best contributions will be moderated and appear within minutes on the largest digital display board at King's Cross. Submissions will be judged by Yoko Ono and leading Scottish poet, Jackie Kay. As well as being displayed at the station, the poems will also be presented at King's Place, the arts centre next to the station.

Haikus are a form of Japanese poetry that is believed to be one of the oldest continually-used poetical forms in the world. Haikus in English usually appear in three lines, to parallel the three metrical phrases of Japanese haiku.

"I liked the idea of doing something that combined an old form with a very new form," said Jackie Kay. "People could do a haiku on the way to work and it's a good way to exercise the brain. It's like the sudoku," she added.

Commuters have to "Tweet" from their mobile phones using their existing Twitter accounts, placing the prefix @kingsplace before their poem.