Tonight marks the start of the town’s festive celebrations with more lights than ever before.

The town’s High Street is expected to be packed for the annual Christmas lights switch-on, which will involve a series of events from late afternoon.

This year the prominent yew tree in St Mary’s churchyard will be lit up for the first time, adding to the extensive array of fairy lights sparkling along the length of the High Street.

The adjoining lime trees will again glow at night after they were threaded with lights for the first time last Christmas.

“The effect was magical last year,” said Edwina Fogg, the town’s mayor.

“I expect it will be even better this year when the yew tree is lit up as well.”

The countdown to the switch-on begins at 3pm when traders and craftspeople set up their marquees in the town centre.

Around 30 artists will be selling their work at a Christmas art market in the town hall, where Santa’s eco-friendly willow grotto will open its doors.

At 6pm children from primary schools around Marlborough will gather at St Mary’s Church to take part in an annual competition, before youngsters parade to the steps of the town hall for the big switch-on at 7pm.

The switch will be flicked by the winners of the choir competition, aided by Marlborough’s 2012 Citizen of the Year, whose identity will have been announced only minutes earlier.

Many of the town’s shops will be keeping their doors open until 8pm while several will be serving mince pies and a hot drink.

Marlborough’s festive celebrations will have Mexican feel for the second year running with the return of Las Posadas, a 25-day procession along the High Street of knitted nativity figures.

Las Posadas symbolises Mary and Joseph’s search for lodgings in Bethlehem and is thought to have been enacted in various forms as part of a nine-day festival in Mexico for more than 400 years.

There two protagonists are usually played by local people who reside in a different house every day during the lead-up to Christmas.

Members of St Mary’s came up with their own version of Las Posadas by displaying the figures in a glass case.

Last year the figures – the main ones representing Mary, Joseph and their donkey – were displayed in a different shop every day on the north side of the High Street from the end of November until Christmas Eve.

The procession will begin tomorrow.

Organisers are hoping shopkeepers on the south side of the High Street will take part this year.

Members of the congregation have now come up with knitted versions of the three kings, which they hope will be displayed in shops along the south of the street.

The two sets of characters are due to be brought together at 3pm in St Mary’s on Christmas Eve for the traditional afternoon service.

Congregation member and retired office manager Sue Pearce, 63, said: “The children loved it and followed the progress of the figures in a different shop window every day.”