Around 50,000 people are marching through Manchester on a union protest against austerity cuts on the opening day of the Conservative Party conference.
Police said the protest was now one mile long as it snaked through the city centre.
The protest is highlighting the impact of Government policies on jobs and spending across the health service, as well as the "rapid sell-off" of the most lucrative parts of the NHS to private healthcare companies.
Following the march a rally will be addressed by union leaders alongside appearances by musicians.
TUC general secretary Frances O'Grady said: "The march and rally will allow thousands of ordinary people to show the Government exactly what they think of their policies.
"Austerity is having a devastating effect on our communities and services, with 21,000 NHS jobs lost over the last three months alone. The NHS is one of Britain's finest achievements and we will not allow ministers to destroy, through cuts and privatisation, what has taken generations to build."
TUC North West regional secretary Lynn Collins added: "Our NHS is under attack and we want to send the strongest message to the Conservatives that we will not stand by and let them sell-off our national treasure."
The march is going through Manchester city centre and will end at Whitworth Park for the rally where a large stage has been set up, draped in banners saying "Save Our NHS", "TUC defends jobs and services" and "No to Austerity".
A Tweet on Greater Manchester Police's account described the march as "good natured".
Another read: "40,000 protestors marching through Manchester and not one arrest."
Later, organisers said the total number of protesters was up to 50,000 and "far more than expected".
This figure was then confirmed by GMP when the force tweeted: "Estimations are that around 50k involved in protest. One of the largest ever policed by GMP. No arrests and everyone safe in the sunshine."