the families are ferried in a white minivan from Staplehurst station through rolling Kentish countryside. The mothers apply a last few dabs of make-up and perfume.
Then the children become restless as they spot their fathers waiting behind the 15ft metal fence. Some will know where they are; others will have been told "Daddy is away working".
No one said family life at Her Majesty's pleasure prison was easy. But keeping in touch with your child's education from prison is another complication. So HMP Blantyre House in Kent has become the first prison to teach courses in the subtleties of the national curriculum, explaining the tests pupils take and the meaning of terms such as "key stage".
On the basis that a happy family life leads to less likelihood of re-offending, prisoners are being coached in how to help their children with their homework and even how to choose a good school.
"It's confusing enough for parents who work in education, let alone someone who's been inside," said Debbie Leach, the prison's head of learning. "A lot of the men feel distanced from it and it's hard to understand the process, especially if they've had a bad experience of school themselves."
The eight-week course culminates in a family learning day, when wives, girlfriends and children visit the prison for a relaxed day of arts and crafts, science, sport and technology.
Guy Ascough, two years into a sentence for drugs offences, says it has helped him to connect with his five children. "I've learned about Sats, key stages and when they're taking their exams. It's opened my eyes. Before, if my boy said he was going into Year 7, I wouldn't have known what that meant," he said.
"If they'd asked me to help them with their maths, I'd have taught them a different, old way. Now I could help out with their homework, and that's a good feeling."
Damon said he was similarly confused when his normally shy 5-year-old son started making strange hand movements and vowel noises on prison visits.
Now, he has learnt they are part of the Jolly Phonics literacy scheme and he has completed some worksheets on it himself.
"I thought it was a bit strange at first," he said. "They didn't do anything like that in my school."
All the inmates say it is tough keeping up with their child's education when they may be restricted to only a few visits a month, in the awkward surroundings of a prison visitor's centre. And their child may not want to talk about school.
But with the help of Blantyre House's staff, Kieran, who is serving a three-and-a-half year sentence for drugs offences, has been able to research his son's homework and post him tasks and guidance.
"It's no different from a dad who's working away from home or if the parents have split up," he said. "I call my son every morning and night."
Kieran subscribes to the school newsletter and plans to attend sports days when he is let out on day release. But he and his wife Sarah admit that keeping tabs on life in the playground is a problem. They fear that Daniel, 7, will be bullied as a result of his father's sentence and that teachers might let other children know about it.
On his first visit to Pentonville, Daniel saw his dad in the regulation yellow bib and assumed he was a road worker. "The trouble started when he learned to read and could understand signs," said Kieran. "One day he said, 'Daddy, you do know you're in a prison?'"
Kieran told Daniel he was there temporarily, painting and decorating. Some of the other families The TES spoke to had simply never broached the subject.
Tricky situations like these can be daunting for teachers. Should you have a private talk with the child or avoid singling them out? Sam Hart, a spokeswoman for Action for Prisoners' Families, says the key is to be sensitive.
"Keep in contact with the parents, be available if they call, support the child and look out for problems with bullying," she said.
HOW TO WORK WITH CHILDREN OF INMATES
Tread carefully. Having a family member in prison throws up complex emotions and carers may not even have told their child where their parent is. If they have told them, they may not wish other pupils at the school to know. Be discreet and respect their wishes.
Be available and approachable if a family member wishes to talk. Find a quiet, comfortable room and make sure any questions you ask concentrate on issues affecting the child's welfare. Inquiries about the nature of the crime may seem nosy or judgmental.
Remember a parent in prison has the same right to be involved in their child's education, school choices and exam choices as a resident parent, unless there is a court order restricting access. Support the child to send samples of their work if they wish, and forward reports and newsletters.
Conflicting emotions will be stirred by arrests, trials and prison visits.
So will the fact the child may not be able to share their successes with both parents. They may truant, become withdrawn or angry with authority.
Make time to listen but do not treat the child as a victim or be over-protective.
Source: the Ormiston Trust. It will be publishing new guidance in July, www.ormiston.org