WHERE did it all go wrong for David Cameron?

Less than three months ago he was leading a Conservative Party government enjoying a majority in Westminster for the first time since the 1990s.

Today he's not even an MP.

Unless I was napping on the job and missed some obvious signs, I can't be the only one who was caught completely off guard by his resignation as MP for Witney, one of the safest Tory seats in the UK, on Monday.

The man himself claimed he was concerned he would become a distraction on the backbenches, and there's certainly an element of truth in that.

But really the reason for the rather ignoble end for the man who at the start of the summer seemed to be quite comfortable in Number 10 can be summed up in one word - Brexit.

It's no great secret that the former Prime Minister never really wanted to hold a referendum on the EU, but he couldn't ignore promising to hold the vote was a major part of getting him back into Downing Street last May.

To his credit, he made good on his vow, and in doing so doomed his own political career.

How different it could have been if he'd joined his mate Boris and campaigned for the Leave campaign.

But, if the record of previous PMs is anything to go by, something tells me he'll land on his feet.

* Speaking of Brexit, it's not going away any time soon.

AMs returned to the Senedd yesterday for the first time since the summer break, and barely a few minutes went by when someone wasn't either blaming the result of June's referendum for some terrible woe, or claiming it was the start of a bright new future for the whole of Wales.

So if you're as sick of terms like 'single market access' and 'article 50' as I am, brace yourself, it's only going to get worse.

* While it's the proposals included in the Welsh Boundary Commission's review of constituencies in Wales to create a single Newport seat and scrap Islwyn which have made the headlines in Gwent, there's another element which could cause a bit of upset.

Monmouth is currently the only constituency in the region held by a Conservative MP, David Davies. But, if the proposals to merge a large chunk of typically Labour-voting Newport East into the area go ahead could cause a bit of an upset.

True, Mr Davies held onto the seat with a very comfortable majority last year, winning 23,701 votes, almost twice as many as his closest rival, Labour's Ruth Jones.

But there's no denying the adoption of thousands of residents of a largely Labour supporting area, along with the loss of Croesyceiliog and Llanyrafon to Torfaen, could upset the balance of power on the eastern edge of Wales.

David Davies is a popular guy in Monmouth and it would take a lot to unseat him.

But I'd be surprised if the thought hasn't at least given him pause.