By any standards, she's had an extraordinary year, with her own elevation to Downing Street just one of the momentous changes of the last 12 months.

But for Britain's Prime Minister, one thing will not be changing, and that's the way she will celebrate Christmas.

And as for hundreds of thousands of Christian families throughout the country, her celebration of the day that marks the birth of Christ will begin with a church service.

In an exclusive interview in the Christmas issue of the Radio Times, Theresa May said that this Christmas, she will be doing exactly what she's done every Christmas for the last two decades.

"A quick drink with friends in our village and then the churches in my Maidenhead constituency come together to put on a lunch and entertainment for older people who would otherwise be on their own," she said of her plans.

"I have a drink and chat with them then go home and serve up my own meal."

Asked if she had any idea, last Christmas, that she might be Prime Minister this Christmas, she admitted: "Politics is an interesting business, things happen. In this case, obviously, they happened rather more quickly than people had expected. But no, I had no idea."

She reveals she cooks her own Christmas lunch, and she and her husband Philip will be feasting on goose rather than turkey as they have for the last few years.

As a vicar's daughter, she takes the religious side of the festival seriously. "Throughout my life I have been going to Midnight Mass on Christmas Eve and church on Christmas Day morning. As a child I had to wait until my father had finished his services before I could open my presents."

This always felt like a long wait, she said. "Others I knew would be able to open their presents first thing in the morning."

She was an only child, and her mother played the organ, so she always sat beside her in church. 

"When you first lose your parents, Christmas is hugely, hugely important. Now I enjoy Christmas with my husband Philip and we keep up the tradition of going to church. But, of course, it does remind me of my parents," May added.

She also enjoys the Christmas TV schedule. 

"I always like to see Doctor Who on Christmas night, if possible, and a nice Agatha Christie to curl up with. David Suchet was a great Poirot – he got him to a T." She used to enjoy The Avengers with Diana Rigg and then Joanna Lumley. "But I don't think I thought about it in those terms. I have never had a female role model – I've always just got on with doing what I am doing."

She also said she enjoys watching Strictly but has found her Saturday evenings this year have been too busy and so has missed Ed Balls' dancing.