CLEARLY the life of a Government minister doesn't afford much "me" time.

We're just about to settle down for a chat when Damian Green's mobile rings.

He makes his excuses and heads for the privacy of the office next door, inviting me to pour the coffee.

When he returns he tells me his department needed a decision on the fate of an immigrant about to be deported; when last ditch appeals are lodged the final adjudication is left to him.

"This happens probably five times a day," he says.

"They're quite frequent at weekends so it's a prominent part of my role as secretary of state and I have to be on call all the time to make these decisions.

"They can come quite literally within an hour of the plane taking off."

It hardly needs saying that immigration is a hot potato, but Mr Green tells me he followed the brief for five years before becoming minister and he rattles off the statistics.

"In the course of Labour's time in power net immigration was something like 2.2 million people.

"That's two cities the size of Birmingham in 13 years.

"You can't continue on that basis and our policy is to bring the level of net immigration right down."

He believes some Labour politicians had genuinely believed that by opening the doors they would help grow the economy by injecting cheap labour.

"But the effect of that was obviously to change the make up of Britain – particularly big cities – very quickly.

"As it turned out it produced a lot of social stresses around growth that's had a whole load of undesirable effects.

"Economic immigration was wrong, and the social consequences of Labour's immigration policy were very bad."

Working on average 80 hours a week, he likens his roles as member for Ashford and Government minister to having two jobs.

His daughters, now aged 21 and 18, didn't see as much of him as he would have liked when they were growing up, although he "tried to be there for the important things".

Fridays are spent in his constituency and earlier we had met at Smarden Primary School.

The children quizzed him on what his dream job would be and I learn that when he was 10 he wanted to open the batting for England. He's then asked if he's proud to be English.

"Let me be clear, I'm Welsh," he replies. "I'm proud to be Welsh, but very proud to be British."

Later Chris Huhne announces he is stepping down as secretary of state for energy and climate change to "clear his name" of perverting the course of justice.

I ask if Mr Green has his sights set on a Cabinet post and would he be interested in Mr Huhne's old job?

"My ambition is to serve as immigration minister as long as I can, as long as the Prime Minister wants me," he replies in about as non-committal a way as possible. But it's probably just as well; Ed Davey got the job.

Normally, he explains, Fridays are busier than today.

As he begins to pack his ministerial case, the conversation turns to his arrest in 2008 and it is clear the scars run deep. "Like everyone else, I couldn't believe that in this country a member of the opposition could be arrested for political activity," he says.

"I was incredibly angry that it had come to this and I think from very early on it was clear it was a horrible mistake that the police and previous Government had made and they just took months to admit it."

Mr Green's "crime" had been to publicise sensitive documents leaked to him by a Home Office insider – meat and drink for opposition politicians since time immemorial.

Precisely who in the Government of the day sanctioned his arrest remains a mystery. I suspect he blames someone but, if he does know, he isn't letting on. "Who can tell?" he says.