“NOT a good time!” barks a stressed nanny, arms aloft, who answers the door to a Liberal Democrat canvasser at tea-time. “There are children being sick,” she explains, gesturing beyond her.

This is Richmond upon Thames, the southwest London borough where nannies are found even in former council houses and the chief competition for the orange Lib Dem billboards comes not from Tory posters but from estate agents’ hoardings.

With its high proportion of working parents and booming property market, Richmond is a testbed for David Cameron’s commitment to green politics as he strives to convince affluent professionals that his party has changed. The Tories won control of the council four years ago but are under siege from the Lib Dems in a battle where environmental policy — recycling, tree-planting, street cleaning and the upkeep of parks — is at the forefront.

The Lib Dems ran Richmond for 19 years until their defeat in 2002, but have since rallied and won five by-elections. The Tories are defending 34 seats, and the Lib Dems 19. There is one Independent, a Tory who joined the UKIP. Both local parliamentary seats have Lib Dem MPs.

On the evidence of a night’s canvassing across Richmond, doubtful Tory supporters have yet to be convinced by Mr Cameron’s green agenda.

Serge Lourie, leader of the Lib Dem group, is basing his attempt to seize control on a promise of doorstep recycling of plastics and cardboard as well as improving secondary schools and using £54 million reserves to cut council tax. As he calls at former council houses in Kew he finds Yunis Khan, a Green Party supporter. What did he make of Mr Cameron going green? “I basically see right through him,” says Mr Khan scornfully.

A few doors along he meets Mary de Hoyte, listed in his records as “probable Tory”, fretting in her apron about her husband’s health and a cracked pathway. Mr Lourie makes a note to contact social services and the housing association. If green policies do not resonate, pavement politics kicks in.

Across the borough in Twickenham, a group of Tories is using Lib Dem tactics to defend seats in St Margaret’s ward: very local campaigning with surveys and colour newsletters for each street. Here, too, the environment is a priority. “Preserve our green and leafy borough,” one says. Mel Stride, who lives outside the ward but has been brought in to co-ordinate its defence, says that the Tories must hold wards like this to keep power.

Tony Arbour, the council leader, says that Richmond Tories went green long before Mr Cameron, and calls his the “cleanest, greenest, safest” London borough. He is proud of planting 1,000 trees, many of them cherries now in bloom.

Jeanne Hill, 83, who opens her door on a chain to Tory canvassers, likes Mr Cameron but when she is asked about his trip to the glaciers her face clouds. “We want to think in terms of what happens here,” she says.

Down by the Thames, James Page, a Green candidate, is told by Terri Gibbons, a disillusioned Tory: “I didn’t like the way he was dragging the dogs about” — in reference to Mr Cameron’s ride by dogsled. “I wouldn’t have picked David Cameron, quite honestly.”

Amy Harvey, 34, who previously voted tactically for the Tories, is equally unimpressed by his Arctic excursion. “How did he get there?” she asks scornfully. “He went by plane.”

Both women tell Mr Page they will seriously consider voting for the Green Party. The Greens, fielding 12 candidates, admit they can only aim to influence the council’s agenda.

The young canvassers of the Labour Party, which is contesting only 38 out of 54 seats, admit that their best hope is to get a foothold on the council. Labour’s canvassers carry a bundle of unused Dave the Chameleon leaflets.

The newsletter they push through letterboxes attacks the Lib Dems. Here, in the battle of Richmond, the objective is not defeating Mr Cameron’s green Tories but stopping the onward march of the orange hordes.

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