The Bill threatens the very principles on which the National Health Service was founded by turning it into a business where taxes will pay for private companies to provide healthcare, meaning profit will come before patient care.

These reforms are being pushed through at a time when the government is asking the NHS to make unprecedented cuts. Despite Government assertions to the contrary, deep concerns about the Bill are held by practitioners and patients from across the health service. They are also shared by many of the coalition's own supporters, including a number of MPs and Peers, who have criticised what health secretary Andrew Lansley is trying to push through.

The TUC says: "The Bill is still in the House of Lords and this is our best chance to change the proposals before it returns to the Commons, where the government can rely on party whips to get it passed.

"We still have time to stand up and defend the NHS – and show peers, MPs and ministers just how unpopular these proposals are."

Trade union members and other NHS users are urged to show their support by coming to the rally in person, or pledging to attend a 'virtual rally' live online.

Those who can't get to London will be able to tune in for a webcast of the live event, and will be asked to make as much noise online as they can by tweeting, blogging, commenting and sharing it on social networks.

To register for a place in Central Hall or to join the 'virtual' rally online, visit the TUC website.