SIR - Last week, to a fanfare of gales and unprecedented flooding, Gordon Brown became Prime Minister.

If he had any doubt before last week which of the challenges that face him is the most pressing, then he has had a timely reminder that it is climate change.

It is ten years since the Government, of which Mr Brown was a senior member, first came to power. That New Labour' government made bold promises about cutting emissions of greenhouse gasses.

They did not, however, follow up their promises with the necessary policies and now ministers are having to admit that they will not meet their own targets.

Though a party to those past failures, Mr Brown now has the power to make amends.

Gordon Brown will take over responsibility for a proposed law - the Climate Change Bill -which the Government has already introduced into Parliament.

If he is serious about tackling climate change, Mr Brown will have to ensure this proposed law is up to the job, for the current Bill just is not tough enough. Its targets are too low to stop dangerous climate changes and it does not even include emissions from aeroplanes.

Worse still, the current proposal is to monitor targets every five years - a period that will span more than one government term, making it easier for succeeding administrations to blame their predecessors, rather than themselves, for missed targets.

Stephen Whitehead, Ashmount Mews, Mytholmes Lane, Haworth