Tens of thousands of people in Sussex who say they are too ill to work will face a tougher time getting benefits under a plan to tackle Britain's "sicknote" culture.

From October next year individuals applying for incapacity benefits will be asked to undertake a new test to establish what they are capable of doing, rather than simply having their disabilities measured, Work and Pensions Secretary Peter Hain said this week.

The new regime, which will initially cover only new claimants, will eventually be imposed on all those receiving incapacity support. As of May this year there were more than 50,000 such people in Sussex.

The harder test will assess claimants' abilities to perform certain work-related tasks, such as using a computer keyboard and mouse. Current tests on walking unaided and climbing steps will be scrapped.

Those deemed unable to work will be entitled to the new Employment and Support Allowance, while those considered to have some capacity to work will be required to show they are making efforts to find employment, or lose payments.

Just half of claimants are expected to pass the new test, called the Work Capability Assessment, compared with the 60 per cent who pass the current Personal Capability Assessment.

It means 20,000 people per year could be stopped from entering the sickness benefit system - and those already in it could see their payments withdrawn.

Mr Hain said the Government wanted to work with people to get them back into jobs and help them stay there.

He said: "We know that many people want to work - work is good for you and your long-term well-being and we don't think it's right that in the past people were effectively written off.

"Currently, there are many people sitting at home in the belief that they are unemployable, with no life choices or long-term prospects because they do not think their illness or medical conditions can be catered for in the workplace.

"But this is just not the case. Many people with such conditions are perfectly able to take up successful careers, if the right support is in place."

But TUC general secretary Brendan Barber said: "Removing benefits or introducing new tests will only force people back to work before they are ready. This will not benefit UK business or the taxpayer."

There are currently 2.64 million working age people claiming incapacity benefits - including 53,810 in Sussex - which cost the country nearly £12.5 billion in 2006/7.

Table: Incapacity benefit (May 2007) Council area Claimants Adur 2,040 Arun 5,000 Brighton and Hove 12,790 Chichester 2,580 Crawley 3,280 Eastbourne 4,220 Hastings 5,480 Horsham 2,470 Lewes 2,890 Mid Sussex 2,660 Rother 3,080 Wealden 3,390 Worthing 3,930 TOTAL 53,810