He was known as "Spreadsheet Phil", and, as Chancellor of the Exchequer, Philip Hammond was likened to an accountant with a reputation for being - well, frankly - boring and rather dull.

But after quitting in the final hours of Theresa May's premiership to deny Boris Johnson the satisfaction of sacking him, he has turned into a quiet assassin and the new prime minister's most deadly Conservative opponent.

Even before voting against the government in a dramatic late night division - and having the whip removed for his pains - he was on the offensive.

When he rose in the Commons early on during the exchanges following Mr Johnson's G7 statement on Tuesday, there were cheers from the opposition benches. Around him on the Tory side of the chamber, there was a nervous silence as MPs winced.

His question, not surprisingly for a details man, was forensic. Nine days into the 30 that the PM requested from Germany's Angela Merkel for a new Brexit deal - Mr Hammond noted - she claimed she had not seen any proposals from the UK.


Speaking slowly and deliberately, as ever, he challenged Mr Johnson to publish the proposals "this afternoon", adding: "So that those of us who are considering what to do later today have the benefit of seeing them."

And for good measure, the tall, slender and willowy Mr Hammond - unaccustomed to speaking from the government backbenches after nine years in Cabinet - urged Mr Johnson to send his proposals to Brussels "without delay". Ouch!

In other words, Mr Hammond was suggesting that he didn't believe the proposals for a new deal exist and that the prime minister has no intention of negotiating a deal and is instead hell-bent on a no-deal Brexit.

Mr Johnson is not a details man, at least not on the evidence of this performance. His Commons statement and the subsequent exchanges were full of Boris bluster as well as evasion and obfuscation - and he clearly had no answer for the former chancellor.

Mrs Merkel had been making an "elementary point," he claimed. Really? That's not how her words were interpreted at the time of their meeting in Berlin. She was saying "we could easily do a deal", said the PM, "and we certainly shall".

As chancellor, Mr Hammond's Tory critics claimed he placed too much emphasis on the economics and ignored the politics. Remember his controversial claim - reported to have been made at a cabinet meeting - that "public sector workers are overpaid"?

But he used to revel in the "Spreadsheet Phil" nickname, eventually referring to it in the Commons. After all, for a Chancellor of the Exchequer, being seen as grey and dull - as the UK's bank manager, if you like - is actually quite a compliment.

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Think Sir Geoffrey Howe and Alistair Darling. Flamboyance is not what the nation is looking for in the keeper of its purse strings. Denis Healey and Ken Clarke were different beasts: big, extrovert political bruisers. That was never Mr Hammond's style.

But now, in recent weeks, Mr Hammond has started landing some bruising political blows on Mr Johnson - for whom he clearly has a barely disguised contempt - and developed a new persona: the outspoken and tenacious cheerleader of the opposition to a no-deal Brexit.

All this despite Mr Johnson's threat to deselect and bar from standing in the general election any Conservative MP who votes against the Government in this week's Commons titanic trial of strength.

Mr Hammond's Commons clash with the prime minister was not his first during the day. A few hours earlier, his long, slim legs strode up Downing Street - just like old times - for a showdown with Mr Johnson inside No 10, along with fellow members of the so-called "Gaukeward" squad, named after former cabinet minister and Mr Hammond's fellow anti no-dealer David Gauke.

The prime minister had been "unconvincing" in the meeting, a source told Sky News afterwards, and he did not provide a "reasonable answer" to questions and was "rhetorical".

The source added: "No convincing proof was given that a real negotiation is taking place."

It was this last point, obviously, that prompted Mr Hammond's rapier-like forensic question in the Commons chamber later. It was designed to embarrass Mr Johnson and it did.

Earlier, Mr Hammond had given an acerbic radio interview, twisting the knife in the PM and his controversial adviser Dominic Cummings. ''This is my party," he declared. "I've been a member for 45 years. I will defend my party against entryists who would turn this party into a narrow faction."

He was in feisty form, having been reselected as Conservative candidate in his Surrey stockbroker constituency of Runnymede and Weybridge on Monday evening, in a move designed to fast-track the process and thwart moves by Mr Johnson and his allies to deselect him.

"There would certainly be the fight of a lifetime if they tried to," he said in his interview. "Spreadsheet Phil" was baring his teeth, having acquired some political cunning at last.

So this week it's not the prime minister's new rescue puppy Dilyn that Mr Johnson should worry about biting him.

But a smart and determined political opponent - often underestimated until now - snapping at his heels on a no-deal Brexit.