Analysis By Peter Henley BBC political editor, south of England

Once again the South of England's local elections are a key battleground, a test of Conservative credibility.

Year after year there has been confident talk from the Tories, but in their Southern heartland they've been found wanting. Will the Howard effect change all that?

Top of their target list is the Labour stronghold of Reading (Lab 36 LD 6 Con 4).

For twenty years the Borough Council has been Labour controlled. But the Conservatives claim the arrogance of power has crept in.

The de-selection of Reading East MP Jane Griffiths was bloody and acrimonious, with talk of a male mafia centred on the council.

Accusations of financial mismanagement have been flying around.

Expect a fall-out from disenchanted voters and party members and a vigorous Conservative campaign, though despite boundary changes and all-out elections it would be a surprise to see the Tories take power.

'Knife-edge'

The Conservatives are pressing Liberal Democrats in Winchester (LD 29 Con 18 Lab 5) and Worthing (LD 18 Con 17 Lab 0).

Last year the Lib Dems lost six seats in Winchester, where Mark Oaten is MP, and the Tories have tapped into local campaigns on affordable homes, traffic congestion, phone masts and planning/conservation issues.

In Worthing The Lib Dems are also on a knife-edge, with a majority of just one over the Conservatives, and all seats up for election. Basingstoke (Lab 15 LD 15 Con 26) is another bell-weather seat, currently run by a Labour/ LD coalition.

If the Tories can't take these the revival is over.

Council tax rises have seen vigorous debate across all councils.

But no-one has ended up capped, and it's still not clear whether local or national government are perceived to be at fault.

We may get a clue at Weymouth (Lab 13 Con 11 LD 6) in Dorset, Labour's most marginal parliamentary seat. Voters shouldered one of the largest rises in the country two years ago at 58 percent.

It has been lower this year - but all seats are up for re-election with Labour and Lib Dems the largest parties.

It is decision time in Portsmouth (Lab 11 LD 16 Con 15), where no party have overall control and all three parties are jockeying for power.

A major local issue is the building of the Spinnaker Tower, which is five years late and has cost taxpayers more than ten million pounds.

Who is to blame? Labour, Lib Dem and Conservatives have said "not me".

In Southampton (LD 19 Lab 17 Con 12) voters have had a few months' taste of Lib Dem control, with some controversial spending decisions on leisure facilities.

But as in neighbours Portsmouth, the political balance is a delicate three way split. Will the voters give a decisive verdict?

The Greens hope for a revival in their fortunes in Oxford (Lab 29 LD 15 Green 3 Ind 1 Con 0).

Once a healthy growth area, they've lost seats in recent by-elections. Here the left-wing alternative to Labour has had some success with an Independent Working Class councillor.

Will they stand in more seats, moving the anti-war coalition forward? In Bournemouth and Portsmouth there are candidates for Respect.

We will know when nominations close whether the BNP and UKIP are fielding more candidates than last time.

The big question, though, is whether the Conservatives can finally get it back together in the South.