Emmanuel Church, in the Weston Favell Shopping Centre, was closed yesterday to allow police and scenes of crime officers to investigate the damage, which took place sometime between 7.30pm on Wednesday evening and 5am yesterday.

The vandals, who it is believed got in through a skylight, trashed the coffee shop, sports hall and toilets and caused minor disruption in the main church hall below.

Rev Margaret Johnson said: "We've all been in such shock this morning. We think it's probably kids by the kind of damage that's been caused but we don't think it was premeditated. It was probably just mischief that escalated."

The vandalism – which includes graffiti on the walls, coffee granules crushed into the carpet, egg shells on the kitchen floor, food smeared on the walls and paint poured over the sports hall floor - was discovered at about 5am yesterday morning by the church's cleaner, who called police.

Rev Johnson said the whole experience had been "horrendous".

She said: "We will have to shut the coffee shop for two days while we clean up which will mean about a £500 loss, maybe more, and we'll need to redecorate and probably have a new carpet so the cost of the clear-up will probably run into three figures as well. It's pretty grim.

"But it's not just us and our customers who have been affected. We hold classes and provide a meeting place for community groups, which we have had to turn away.

"Our staff are a mixture of paid staff and volunteers and some of the volunteers have learning difficulties.

"They find it very difficult to understand something like this and it's quite frightening for them. The people who did this have no idea just how big an impact it has on so many people and the cleaning up operation and making good is probably the smallest part of it."

A spokeswoman for Northamptonshire Police said: "We have gathered evidence after a burglary at the Emmanuel Church some time between 7.40pm on Wednesday and 5.30am on Thursday. Our investigation is underway but it takes time to put all the evidence together.

"We are completing our inquiries at the moment to find out who was responsible and how they got into the church."