The first group of NHS volunteers have left for Sierra Leone to help in the fight against the deadly Ebola virus.
Around 30 GPs, nurses, psychiatrists and emergency medicine consultants left London Heathrow just after 17:00 GMT, bound for the West African country.
They will train for a week in the capital Freetown before moving to treatment centres across the country.
The Ebola virus has killed more than 5,000 people in the current outbreak, including 1,267 in Sierra Leone.
Once in the country, the healthcare professionals will be diagnosing and treating those who have contracted Ebola.
Donna Wood, senior sister at Haywood Hospital in Staffordshire, was among the volunteers to leave on Saturday.
"I'd been following the stories on the news so when I saw an email from the NHS highlighting the Ebola situation in Sierra Leone, and calling for volunteers, I felt I had to act.
"I knew I could use the skills I've got to make a difference and join a team to help bring the disease under control."
Ms Wood said she had received "gold standard" training.
She added: "We're very lucky in this country to have the NHS, the staff and the skills - it's just not the case everywhere else.
"My parents and the whole family are proud of my decision to go."
By Megan Bramall, BBC News
As the NHS volunteers waited at the check-in desk, there was one thing they all said they would miss: Human touch.
Julie Flaherty, a consultant nurse from Salford Royal Hospital (pictured below), had tears in her eyes as she said she would miss hugging her husband after a long day.
"That will be a challenge," she said.
Cath Nixon, a public health nurse from Oldham, echoed this.
"I think sometimes when you're having a difficult day then it's that what you need. A hug. And we won't have that."
But the oldest volunteer heading to Sierra Leone, Dr Gordon Gancz, said the group had come up with a special plan for Christmas Day.
"We all plan to put on our full protective equipment to give each other a Christmas hug."
Meet the medics behind the mask (Department for International Development link)
The NHS volunteers have been preparing with intensive training at a Ministry of Defence facility in York.
More teams of volunteers are set to leave in the coming weeks after hundreds came forward to offer their services.
Gareth Ross, a paramedic from Yorkshire, said he had "never experienced anything like" the sense of morale and teamwork felt during the training.
"As paramedics we're often going into the unknown, sometimes in hostile environments. It's just a matter of applying that to a different situation," he said.
Consultant psychiatrist and volunteer Dr Martin Deahl said: "Someone has to do this job and if we don't do it there, it's going to get here.
"I'm going to be looking after people's mental health and mental wellbeing. It's going to be fairly traumatic by any standards, but the way you do that is to set an example and roll your sleeves up."
Chief medical officer Dame Sally Davies said: "The fact that more than 1,000 have come forward so far is a real testament to their commitment to public service."
Speaking from Freetown, head of the UK's Department for International Development Joanna Reid said Sierra Leone was "absolutely determined to fight" Ebola.
"[Volunteers] will be looked after by NGOs that are experienced in this country, have been working here and also have a sense of team spirit," she said.
Prof Tony Redmond, head of the charity UK-Med, which organised the deployment, said he was proud of the "selfless volunteers".
There are now 1,000 British military personnel, scientists, healthcare and aid workers helping to tackle the outbreak in West Africa, International Development Secretary Justine Greening said.
She added: "Every one of these NHS heroes will play a vital role in the fight against Ebola. It is only because of their combined efforts that we stand a chance of defeating this disease."