Thursday's march is part of Deafblind Awareness Week and comes as charities Sense and Deafblind UK publish a report showing that access to specialist services is a lottery, depending on a person's postcode.

March organiser Graham Hicks, who is himself deafblind, said: "Deafblind people need support workers as their link to the world. What you get now is pretty much an accident of geography.

Being both deaf and blind can be very isolating

"This report confirms that we are some of the most discriminated against and socially excluded people in Britain.

"We need the government to legislate and provide the funds so deafblind people have access to these vital specialist services."

Sense is calling on the government to ensure services are available nationally and to invest �12m a year in improving services.

It says in the long term this could save money, allowing people to live more independent lives and avoid costly residential homes.

Some 23,000 affected

About 23,000 people in the UK are both deaf and blind, many with other disabilities as well.

In previous years, many were born disabled after their mothers caught rubella or German measles during pregnancy.

But this is less common today, with meningitis, car crashes, babies born very prematurely and genetic conditions such as Usher syndrome a more likely cause.

And as Britain's population ages, the number of elderly people becoming deaf and blind is increasing.

The charities spoke to 366 people for their report, Out Of This World.

More than three quarters of those interviewed said they had no specially trained one-to-one support worker, although seven out of 10 said they needed the services.

Some who had support workers described them as "a lifeline".

Four out of 10 said they felt like prisoners in their own homes because they lacked the support to help them go out.

Only one in eight believed they had services which met their needs.

'Frightening condition'

A spokesman for Sense said in some areas there were no specialist services for deafblind people, while in others the situation was good.

Adequate provision could ensure people were not socially isolated and could mean that many could go out and, in some cases, go to work, he said.

"Being deafblind can be a very isolating and frightening condition," he said.

"If you are blind, you may be able to go out and cross the road because you can hear the traffic.