Lindis Percy could be a Joanna Trollope heroine - except for the fact she's been arrested 150 times. EMMA COOK met her
There are pockets of the Establishment whose hearts must sink at the mention of Lindis Percy. Policemen, prison warders, prison governors, security guards, US base officials, who, over the years, have wished this gentle-mannered chaplain's wife would take her barrage of awkward questions elsewhere. No chance. Lindis is driven to ask "Why?" at the point many of us would settle for "So what?" She just keeps going; writing letters, trespassing on US bases and appearing in court.

"I've always been a bit outraged by people in authority saying, `That's the way it is' without being accountable or having to explain their actions," Lindis smiles, and pours Earl Grey tea into dainty blue and white china cups. The ritual of tea is still a novelty for Lindis. This is her first interview since she was released last month from Bullwood Hall Prison in Essex after a nine-month sentence. "It's the mundane things you miss - drinking from proper cups rather than plastic ones," she says.

Lindis has stayed in more prisons than most hardened criminals - four including Holloway - and she's been arrested 150 times. Her most recent sentence was for breaching an injunction banning her from RAF Menwith Hill in Yorkshire, the largest regional intelligence station in the world.

Lindis, a member of the Campaign for the Accountability of American Bases (CAAB), trespassed at Menwith Hill to expose their covert activities - they have the capability to eavesdrop on 1 million phone calls, faxes and e-mails per hour without a warrant. She is outraged that American bases have these powers in Britain. "They call themselves RAF but they're not. It's an absolute con. These bases are targets for terrorist attacks, which is so frightening when you see what the US are doing around the world. One day people will look back and say, `Why did we ever allow them here?'"

Lindis is 57 but seems much younger. She darts around the kitchen, talking endlessly. She looks healthy too, considering where she's just been, with a deep golden tan and lively pale-blue eyes. She's re-painting the house with her husband, Christopher, an industrial chaplain. When she's not in trouble with the law, she is a midwife and health visitor. She loves her work. Behind her, there is a montage of family photos; of her grandchildren and three children, grown-up and scattered around the world. "They do worry and get anxious but they know my campaigning is something I'm not going to give up; they know it wouldn't be right for me."

When she was in prison, she felt she had to reassure her family, to protect them from what was really happening. She served a few months at the same prison as Myra Hindley, Highpoint, until officials deemed her, "incitable and difficult to manage". "I would ask questions without shouting or getting violent," she says. One warder, she says, "would shout, `Oi, Percy, over here', and I said `I wonder if I may ask you to refer to my first name Lindis or my title Miss Percy.' In the end I got a memo sent around instructing officers to call women by their title and surname."

It's easy to see how her amiable yet defiant manner must have infuriated and baffled some of the warders; the courteous chaplain's wife who wouldn't seem out of place in a Joanna Trollope novel, unfailingly polite yet intransigent when the rules rankled. Once she settled to read a book in the prison grounds and was asked to move three times. The last time she refused. That evening all the inmates were grounded.

It's hard to imagine what other prisoners must have made of her. Lindis describes how some women cheered after she stood up about yet another petty rule. Yet her freedom to rebel made others resentful - prison was more of a campaigning issue than a fact of life for her; she had less to lose. "Women don't speak out because they're waiting for parole. They have to be Miss Goody-two-shoes - that's a huge barrier to questions being raised by inmates," she says.

Some were less appreciative of Lindis's outspokenness on their behalf - they made it clear they thought she was being given preferential treatment. "There are some hard, hard women in there. The class thing was obvious. There were those who thought I was a toffee-nosed bitch."

She doesn't seem to have been particularly scared by them. Or the officers either. Only one experience has really shaken her - "In Holloway, when I was forcibly strip-searched. I was followed into a bare cell by four officers. It was awful, they pinned me down. It was everything to do with control. I went into a classic reaction - absolute shock. I couldn't eat for two weeks."

There is something childlike about her insistence to just keep asking "Why?" Perhaps it's that quality that protects her from the fear of the very real violence she often provokes. She has been assaulted before - one officer, she says, knocked her chair so that she banged her head against a wall. Another threatened her. When her car was parked near Menwith Hill, someone poured sugar in the petrol tank then slashed the tyres. None of this seems to intimidate her. If anything it makes her more determined. "I don't want to rest now - time's too short," she says.

She has no idea where this determination to confront injustice stems from. Her father was a clergyman and she was the youngest of four children. "I was a mistake," she says, "and mistakes are sometimes difficult." Or more prone to feel outraged, perhaps. From the age of seven, she found bullying insufferable. She walked out of school once when a teacher hit her. "I could never stay quiet when there was an injustice. If someone was being bullied I would think, `That's just not right'. Maybe it's her religion - she is a Quaker. "I do believe we're equal in the sight of God and if someone pulls rank I find that difficult."

The political outrage came later, when she met Christopher. "He has always been political and he was very influential in my awakening to a lot of issues."

When she came out of prison her husband was there to meet her at the gates. They decided to go straight on holiday, but the car broke down. "We were sitting on the side of the motorway waiting for the AA and I couldn't help smiling to myself. It was a gorgeous sunny day. Breaking down was bad luck but to me it really didn't matter. I was free."

She smiles and pours herself another cup of tea.