Guto Thomas Political correspondent

The Senedd, the assembly's home, is accumulating influence

In many ways, the Welsh assembly after 3 May 2007 will bear little resemblance to the institution that came into existence eight years before.

Yes, there will be more than a few of the same old faces, and yes, the Senedd, opened with such pomp in 2006, will continue to provide a political stage for Wales.

But the expanded powers of the third assembly - with its ability to create new laws, devised and moulded to fit the needs of Wales - should be as dramatic a change for the Welsh body politic as the creation of devolution was in 1999.

Before 1999, the ad hoc devolution of powers from Whitehall to the Welsh Office had created a complex and in many cases illogical set of powers that were exercised by the Welsh secretary and his ministers.

The first act of devolution was to transfer this collection of powers to the assembly itself - a constitutionally strange "corporate body", which in its infancy had to learn how best to handle the jagged edges of its limited powers.

But regardless of the growing pains of devolution, this was the moment when for the first time Wales had its own elected government, and the makings of its own civil service.

Politically, this was also supposed to herald a new beginning - "consensus" politics was expected to break down the barriers of Westminster's knock-about style.

This ideal didn't last long, and over the course of the 1999 and 2003 assemblies, the more established conventions of political discourse were revived.

Growing steadily: The assembly is going up the evolutionary path

The only period when positive harmony between the parties surfaced was during the Labour-Liberal Democrat "partnership government" of 2001-2003; while a more negative kind of harmony has existed since then, as the opposition parties have consistently ganged up against Labour rule.

During this evolution, "cabinet secretaries" became "cabinet ministers", in charge of what became officially known as the Welsh Assembly Government - as opposed to the assembly itself.

The split between the executive and the parliamentary functions were de facto formalised, and Welsh politics slowly began to mature.

The official death of corporate body status, and the mutation of AMs in government to become ministers of the crown will be another significant step after 3 May.

On the surface, the picture will not at first appear very different aft the election: 60 AMs will be elected, who will nominate a new first minister, to be conferred by the Queen.

Members of the cabinet and the identity of the new post of counsel-general (the assembly government's legal adviser) will follow in turn - although this may all be a slower process than anticipated, in the likely event of the complications caused by any coalition.

Committees and question times will rattle on in perpetuity - though with a much more focused responsibility for scrutinising the decisions, policies and spending commitments of ministers.

This will be particularly important, given that the assembly government's budget in 2007 will be over �14bn - double what it was back in 1999 - and with much tighter financial pressures on public spending being applied by the UK Treasury.

Could proposals for Welsh laws face opposition at Westminster?

The assembly government will have responsibility for the same areas of policy as in the past - including health, education, economic development, local government funding, rural affairs and the Welsh language.

But over time, the new Government of Wales Act will allow further powers to be devolved, after specific requests have been approved by both houses of Parliament.

Although limited in scope, these "assembly measures" are the next clear step on Welsh devolution's journey. The boundaries will undoubtedly be tested, as some AMs seek to move closer to achieving full law-making powers, independent of any Westminster approval.

The prospect of achieving full Scottish-style powers is already enshrined in the Government of Wales Act, and by the time of the fourth assembly elections in 2011 could become reality - subject to another referendum.