Action for ME, a campaigning body, has joined forces with Westcare UK, a more service-focused charity. The new organisation, which employs around 50 staff, has taken the name of the larger body, Action for ME.
Action for ME's offices in London and Somerset will remain open as will Westcare's Bristol headquarters. However, the merger will result in job losses. Chief executive Chris Clark would not comment on the situation regarding full-time staff, but said: "Some people had been on temporary contracts in anticipation of this happening."
Merger talks were initiated a year ago by Westcare. Clark said both parties recognised that they could do more together.
"Westcare had tremendous success in delivering services but the practice models they developed needed to get more impact nationally. We had developed an excellent name for our campaigns but there was a big hole in our experience on the ground,
"We realise that it is still relatively rare for charities to merge but have been motivated by the desire to provide a better deal for people with ME."
Earlier this year the Government's chief medical officer called on the NHS to provide better services for people with ME, a condition that affects 240,000 people a year in the UK. A Government report on ME (myalgic encephalomyelytis), also known as chronic fatigue syndrome, stated that services should be "explicitly planned and resourced".
"We felt that in this climate there is a real need for a charity that can evaluate and promote best practice on a national level,
"If we can integrate the Westcare expertise on service provision with the information and campaigning experience of ME, we will be in a position to achieve this ultimate goal."
Dr Richard Sykes, founder and director of Westcare, is retiring but will continue to be a consultant.
Action for ME was founded as a membership organisation in 1987. Westcare UK became a charity in 1990, a year after it was set up, to provide counselling services, occupational therapy and residential rehabilitation mostly in the South West.
The Westcare legacy will be evident in the work of the new organisation.
"We are planning to develop more training activities through the 200 self-help groups in the UK that are supported by us,
ME can affect anyone and causes severe muscle pain, exhaustion and memory loss.