Pupils will celebrate the official opening of their new £4 million school building in inner city Bradford tomorrow.

The Rainbow Primary Free School, which runs classes on Saturdays and an extra week of lessons during the summer holidays, started life in a Victorian building in Manningham Lane in 2011.

Now pupils have moved into the bigger Nelson Street development, which has a curved structure to reflect the feeling of a rainbow and a prism-shaped room at its heart where the children can meet and chat.

Tomorrow, the Lord Mayor of Bradford, Councillor Khadim Hussain, will open the new facility which stands on the site of a former fire station.

Chairman of the Rainbow Schools Trust, Amjad Pervez, said: “What a fantastic achievement to bring the idea of the free school to fruition from the hopes and plans such a short time ago, and in such a wonderful setting.

“This is a truly great day, when we can see how happy and excited the children are, and how the staff and parents are already delighted with the new building after just a week. They have state-of-the-art facilities which will really help them all to flourish and excel.”

The school’s policy is to be open to all pupils, regardless of ethnicity, background or faith. Literacy, numeracy and cohesion are high on its curriculum, with no class larger than 25 children.

A spokesman for the school said: “We do invite children in on one Saturday a month and to attend a week during the summer holidays. The idea is to invite them back in so they get refreshed before they start again. It’s not compulsory, it doesn’t form part of the attendance register, but parents are very keen on that.”

Parent ‘Universities’ and parent-teacher-child conferences also help keep families involved.