Hello and welcome to the History Extra podcast from BBC History Magazine, Britain's best-selling history magazine. I'm Ellie Cawthorne.

Today we've got the final episode in our series on Britain's greatest prime ministers.

Hello and welcome to our new series profiling some of Britain's most important prime ministers.

I'm Matt Elton, Deputy Editor of BBC History magazine.

It's 300 years since Robert Walpole became Britain's first Prime Minister.

To mark this seismic moment in the nation's political history,

we asked a series of leading historians to each nominate the two leaders that they believe

achieved most during their time in number 10. So I'm delighted to be joined by Sir Anthony Seldon,

who is the author of a new book, The Impossible Office, which charts the history of the Prime

Minister and also the presenter of a new radio series on BBC Radio 4. Anthony, I wondered if I could start by asking you.

You're someone who, as you say in your book, has spent decades thinking about and writing about

prime ministers. What do you think is our most common misconception about the office?

That the office is, and very nice to be on, by the way, that the office is getting more and more powerful.

You know, I was at school in the 70s and my A-level politics essays were about the Prime Minister becoming presidential, went to uni, came to London, did an, was at LSC, did a doctorate.

The supposition was that the PM wasn't very powerful back then.

Why not?

Because there was a monarch.

And the PM has become steadily more powerful, the office has got bigger and bigger,

that bigger means good, and that now we have, you know, pick out whoever you want,

Thatcher, Blair, Johnson, in effect, a president. And of course, it's absolute nonsense.

So if we head back to the very first days of the office, when and why did the post emerge?

Because Britain had its traumas in the 17th century, a civil war that resulted in the execution

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