A primary school in Watford has been recognised as "outstanding" by the government's education watchdog, just three years after receiving a "satisfactory" rating.

Alison Campbell had only been Cassiobury Junior School headteacher for two weeks during Ofsted's last visit in 2005, when she outlined her plans to improve pupils' standards of achievement.

Now three years later, Mrs Campbell and her staff have impressed inspectors with lively and engaging classroom activities, strong guidance and the use of ICT in lessons.

Cassiobury, in Bellmount Wood Avenue, has 240 pupils aged seven to 11, and on Tuesday, Year 6 pupils came to the end of a Mini-Enterprise challenge to set up a small business.

Following her visit last month, Ofsted's Patricia Cox reported: "The dull grey concrete exterior of the school belies the attractive environment and quiet buzz of productive activity within."

She said there were a number of reasons why pupils are high achievers, pointing out that "teaching has steadily improved and is often extremely good", teachers use questions to measure pupils' understanding, and the school is quick to act where standards are slipping.

Mrs Campbell was also singled out for praise. "The headteacher provides outstanding leadership," Ms Cox wrote.

Since Mrs Campbell took over, she has worked to improve the quality of teaching while making lessons more interactive enjoyable.

She said: "I'm absolutely delighted. It reflects the hard work done by the team. They've really worked hard to make sure we put every child and their needs at the centre of what we do. And it's not just in English, Maths and Science, it's right across the curriculum.

"We've got a fantastic bunch of governors who get involved in the school and play their part."

Ms Campbell also put the school's success down to listening to pupils' suggestions. She said: "They wanted exciting learning. They wanted to know how to improve their own learning and get better. They have been really good.

"The school is like everything in life. It's evolving all the time. We're constantly rethinking how to improve something or keep something at the standard it's at."

In the future, Mrs Campbell said she "would love to see they school building reflecting what goes on in the building".

She added: "It will be hard work to maintain (current standards) but we will do it."

Sue Miller, the Chairman of Governors, said: "I'm delighted. It reflects the hard work and commitment of everybody at the school. We have got a good bunch of governors who all work together. Above all, it's about Alison and the wonders she's done. I'm very proud and very pleased for her. She always puts the children first."