8am - Arrive at the bright and shiny Department for Children, Schools and Families to be met by Suzie McNair, Jim's cheery, mega-efficient assistant private secretary. She assists Jim with ministerial - not party political - matters and she shows me his office. He has school design books, pictures from children, photos of his family and a large bowl of fruit.

8.15am - Suzie and I join Ray, Jim's official driver, in the ministerial Prius.

8.25am - Pick up Jim who, despite a few rounds with Jeremy Paxman the night before, has been in the gym, practising for Sport Relief. We head off to the Mulberry School for Girls in Tower Hamlets.

8.30am - In between checking his emails, running through his speech, and flicking through a sheaf of press cuttings, and sipping coffee, Jim rings a colleague about an excellent Dorset scheme that assists troubled young people. Would it help in Bridgend? Suzie whizzes through her emails. I'm the only person in this car who isn't busy.

9.05am Arrive at Mulberry. Despite the obvious local deprivation, the school is a bastion of vigour and achievement. "Now you can see why I always wear flat shoes when I'm with him," pants Suzie, as Jim charges off, greeting pupils, asking questions and lavishing praise on headteacher Vanessa Ogden. We surge upstairs, Jim leading by a neck, and spend 10 minutes in a lively RE lesson. On the way back Jim chats about physics, dives into a basketball session to ask a question about the Olympics and then it's Q&A time with the students, who describe their recent visit to the UN. "That building uses stone from Portland in my constituency," says Jim, proudly. After a cup of tea he's presented with some beautiful henna pictures. A quick photocall and we're off. He's delighted. "This will be the highlight of the day."

10.30am - As the car crawls past the Tower of London, Jim takes calls from his daughter, catches up with emails and alters the speech he's about to deliver. Who says blokes can't multi-task? (Me, I think. Before I met Jim).

10.50am - Central Hall in Parliament Square and the conference of the National Centre for the Teaching of Mathematics. Jim catapults on-stage to deliver his speech. "Quality teachers are the only way possible to give young people the best education," he declares, launching a new website. Off-stage he is mobbed by mathematicians. Suzie tells me that for his birthday, the department adopted him a monkey from Monkey World.

11.05am - Jim's boss Ed Balls was slated in today's Daily Mail for using a ministerial car to go 150 yards. No danger of that for Jim. "It's nice to walk!" he announces, as we hare across the road, back to the department.

11.10am - Back in his purple-and-white office, Jim reads documents, munches a banana and explains that while ministers are required to carry the can for the government, they can't always know everything that's in that can. Like today's Budget. "We won't hear the details until the Chancellor speaks." Jim enthuses about the day Dolly Parton visited the ministry. He might share Jim Hacker's first name, but Yes Minister this is not.

Noon - My legs are a blur as Jim and I race to the Houses of Parliament. He's carrying a sheaf of papers. "In case I can flick through during the Budget." Being able to grasp quickly what you're reading or being told is the key to being an effective minister, he says.

12.15pm - Punch and Judy time at PMQs and then, at 12.30pm precisely, Alistair Darling delivers the Budget. Back at the Ministry, on the office big screen, I see Jim standing beside the Speaker's Chair.

2.04pm - Jim returns from a press interview to be told he's supposed to be on front bench duty. What's that? "Sitting on the front bench to support whoever's speaking." He decides to do proper work instead.

3pm - Rush back to Westminster to give whistle-stop tour to students from Eltham College, Jim's old alma mater. We zoom up and down stone staircases and corridors and into the exquisite Pugin crypt. Up in the Central Lobby we spy the glowering presence of Alastair Campbell.

4.15pm - Back at the ministry Jim chairs a meeting about the legacy of the 2012 Olympics. It's going well but he's worried he might miss out on a visit to his beloved Arsenal Football Club for the launch of the Year of Reading.

5pm - Home time for me, but for Jim the work goes on. He's got another office meeting, a meeting with a backbench MP and an evening engagement. He can't return to Dorset South tonight because of tomorrow's Sport Relief photocall. When he does get back he'll be working flat out in the constituency.

I am impressed.