Cameron puts environment at heart of poll fight says Jean Eaglesham,Chief Political Correspondent of the Financial Times. David Cameron will today put environmental issues at the heart of the Conservative party's battle for next month's local elections, presenting the campaign slogan "vote blue, go green".

The Tory leader's move to highlight green issues, such as council records on recycling, marks the start of what will be an intense week of campaigning by both the main parties.

Tony Blair and Mr Cameron will be out in London - a core battleground in the May 4 polls - trying to drum up support in an election that could have a significant effect on both their futures. If Labour has a particularly bad result, suffering extensive net losses, the poll could become a referendum on the prime minister.

A meltdown would intensify the pressure from the Brownites for Mr Blair to accelerate the planned handover of power.

May 4 is also a crucial electoral test for Mr Cameron. His party will be looking for a high share of the vote - ideally, above 40 per cent - to give some electoral ballast to hopes they are not heading for their fourth general election defeat in a row.

At the very least, the assumption is the Tories, fighting an unpopular incumbent government, will be able to make net gains. If they fail to win additional seats, the incipient backlash among rightwing members against Mr Cameron's modernising approach could gather dangerous momentum.

The Tory approach appears to be two-pronged. Today's launch of the "final phase" of its local election campaign will be a soft-edged appeal to voters' better instincts. Mr Cameron, in a forward to the launch leaflet, focuses on objectives such as "making parks and public spaces beautiful".

But this will be complemented by a more direct Tory appeal to voters' wallets. George Osborne, the shadow chancellor, will today focus on council taxes, using a walkabout in Labour-led Hammersmith and Fulham to highlight the high rate it charges compared with neighbouring Tory-run Wandsworth.

Mr Blair this month defended his party's record on council tax, saying the average in Labour-controlled areas was £190 less than in Tory-controlled ones.