What does Welsh Secretary David Jones's departure mean?

One immediate question that springs to mind is what does David Jones' departure mean for relations between the Welsh and UK governments?

There was always going to be tension, after all one side is Labour and the other Conservative at a time when David Cameron has called Offa's Dyke "the line between life and death".

But the extent to which there's been disagreement has been a real feature of events over the past year.

Behind the scenes, he was seen by Welsh government ministers as a blocking secretary of state who would get in the way of the devolution of more powers for the sake of it.

David Jones did introduce the Wales Bill into parliament which will lead to tax and borrowing powers for the assembly, and he came out in support of the devolution of income tax to Cardiff Bay so that rates could be lowered.

But he also pulled no punches when it came to the performance of the Welsh government.

Growing divide

One of the last speeches I heard from him was at the annual conference of the Welsh Local Government Association in Llandudno in which he repeatedly laid into the extra building regulations which he said were being faced by the construction industry in Wales.

Regulations and red tape was classic David Jones territory.

One of his central claims was that of a growing divide opening up between Wales and England in some key areas that is hindering economic growth.

His most high-profile recent appearance in Wales was at a conference of infrastructure experts where he said the Welsh government's stance in the row over the payment of rail electrification in the south Wales valleys was putting the project at risk.

This unresolved dispute was his most high-profile row with ministers in Cardiff Bay.

He was adamant the Welsh government was breaking an agreement, and described as a "try-on" Carwyn Jones's constant reference to an interview on Wales Today in which the prime minister said the UK government was funding the electrification of the valleys.

Behind the scenes

The expectation is that his deputy Stephen Crabb will replace him as secretary of state.

If he does, then it will be fascinating to see whether his appointment will mark a new era of improved relations between the two governments on either side of the M4.

If that is to happen, then the first thing Mr Crabb needs to do is navigate an agreement on the valleys line rail row without anyone losing face.

As a whip, Stephen Crabb is used to striking deals behind the scenes but this will surely be a huge challenge.

And if he does introduce a change of tone, then it can only go so far as we enter the general election campaign.

His appointment is not going to change the Conservative "compare and contrast" strategy, despite Welsh ministers hopes of a softening of hostilities.

'Do business with'

Carwyn Jones has just given his last news conference before the summer break and hinted strongly that Crabb is the favoured candidate to replace the sacked David Jones.

Or in the first minister's words, he is "someone we can do business with."

And then there's the relationship between the Conservatives in London and the Welsh Conservatives.

David Jones did not see eye to eye with the leader of the Conservatives at the assembly, Andrew RT Davies (at last, some common ground with Carwyn Jones).

They disagreed on the devolution of income tax and Andrew RT Davies ended up sacking five of his front-bench team for, in effect, siding with David Jones and the prime minister, rather than agreeing with him.

When Andrew RT Davies criticised the model of income tax that was being offered to the assembly by the UK coalition, David Jones dismissed it as being "very much a personal view of his own", rather than the leader in Wales speaking on behalf of his group.

The feeling is the potential arrival of Stephen Crabb may even help matters here, and even coincide with the healing of some of the internal divisions within the party at Cardiff Bay.