Gordon Brown will today appear before MPs for his eighth Budget as chancellor.

He will set out proposals for a wholesale modernisation of the civil service and signal that the Treasury intends to keep a tight lid on spending.

Brown is also likely to outline plans to boost affordable housing in property hotspots following the publication of the Barker review this morning.

And he will confirm plans to merge Customs and Excise and the Inland Revenue - a move which will streamline the tax collection process and lead to job losses.

Central to the announcement will be a significant slowdown in the rate of growth in public spending.

The chancellor will mount a stout defence of his management of the economy - insisting that his growth foreacasts, seen by many as over optimistic, have come good.

Brown also appears set to signal that Britain remains as far removed from the single currency as ever - but is likely to pledge to hold an annual review of his five tests.

He will also target tax avoidance in a bid to maximise the Treasury's take. An onslaught against accountancy firms which advise clients on how to utilise lucrative tax loopholes is expected to feature prominently.

The chancellor may also signal that he wants to secure money sitting in dormant bank accounts for charitable purposes.

Other measures likely to be detailed today include proposals to protect science funding and increase cash for research.