By Gary Eason BBC News Online education editor

And there are wide variations between the incidences of truancy in different parts of the country.

Across the country as a whole, more than a fifth of secondary school pupils - 21% - were absent without permission at some stage, on average for 15 "half days" - the measure used in the official statistics.

Fifteen per cent of primary school pupils were away, for eight half days on average.

Almost everyone took some authorised leave during school time - 92% of the pupils in primary schools and 93% of those in secondary schools.

On average they were away from primaries for 17 half days and 23 in secondaries.

Best and worst areas

The data published on Wednesday is broken down by each of the 148 main education authorities in England.

Overall absences ranged from 11.4% in Hull and 11.3% in Knowsley down to 6.6% in Redbridge and tiny Rutland.

Most authorities did better than the previous year - but in 10 things got worse and there was no change in six.

In primary schools, unauthorised absence ranged from 47% of the pupils in Tower Hamlets and 46% in Southwark, down to 4% in Rutland and 5% of those in the Sunderland, Northumberland, North Tyneside and Durham education authorities.

Looked at another way, the average number of half days of unauthorised absence ranged from 12 in Liverpool and in St Helens, to five in Bournemouth, Bracknell Forest and Shropshire.

In secondary schools, 48% of all the pupils in Tower Hamlets and in Bradford are said to have been absent without authorisation at some point. At the other end of the scale, only 8% in Wirral and 7% in Northumberland did so.

The average number of half days missed ranged from 29 in Reading and 28 in Knowsley to eight in Tameside and seven in Lambeth.

Scottish statistics

In Scotland, statistics have shown that around 7% of young people truanted frequently, 17% occasionally, and 28% rarely.

The Scottish Executive advocates a combination of three approaches - prevention, management, and control.

Prevention means things which try to make schools and classrooms attractive, encourage and support young people so truancy is unlikely.

Management involves dealing with any truancy promptly or seeking help from other agencies.

In the control category are approaches which seek to deal with young people's behaviour - for example through detention or exclusion or prosecution of parents.

What children say

The executive has quoted some of the reasons young people give for not going to school:

"I just felt sick every time I thought about turning the corner and seeing that school in front of me."

I was always in the top class. I just couldn't stand everyone saying I was a swot. After second year I never went back

"I was always in the top class. I just couldn't stand everyone saying I was a swot. After second year I never went back."

"There's nothing I'm good at. What's the point going every day for just to learn what you already know - nothing!"

"I don't mind school but most of my pals just say let's go down the town, so you go."

"The teachers all look down on you because you're from the scheme. It's like you're contaminating their lovely school."

"Mr X makes me stand in the middle of the floor and say I am a prat. It is humiliating. I'd rather have the hassle for dogging it than put up with that."

"You can't go to the toilets or you get beaten up. Half the time you can't go into the playground because someone will do you over, and if they don't get you in school they get you on the way home."

"I stay off sometimes when I'm at my dad's. My mum is really strict and makes me go in even if I've got a headache."

I can be a lot mair use staying in the hoose looking after the weans for my ma

"The only time I don't go in is when I have nae done ma homework. That can be quite often mind."

"Wee white boys all slag me and my family. Sometimes they wait behind a hedge and throw stones at me."

"If I'm late I think well maybe it's better to stay off sick than get a big row an that."

"I often get a sore stomach or a sore throat and my mum just lets me stay in my bed."

"I can be a lot mair use staying in the hoose looking after the weans for my ma."

"I had a puni and it got doubled and I couldn't do it so I just thought I'd no go in."

"I start my milk round at four. If I've been up late the night before I'm too knackered to go to school. I should maybe give it up but it's 45 quid a week and that's a lot of dough."

"The only day I dog it is PE days. I just can't stand it."