The liberation of Bergen-Belsen loomed really large in Great Britain in the immediate postwar. I apologize that I don't have my sources with me, since I am in the middle of a move and all of my books are boxed up, but it have read quite a bit about Belsen in particular and ill do my best to present an overall portrait of the liberation of that camp.

As the British army advanced towards the camp, the camp commandant actually sent out a negotiation party to offer the surrender of the camp to the British. The reason was that the camp was in the midst of a massive typhus outbreak (Anne Frank and her sister Margot died of typhus in Belsen in March 1945, a few weeks before the British arrived) and they were concerned that if the camp wasn't transferred to the British in an orderly manner, the prisoners would all run to nearby towns and initiate a full blown regional epidemic (typhus is spread by lice). Camps in outlying areas of German territory had been evacuated to places in the interior of Germany, as Belsen was, so thousands of sick and dying prisoners from other camps brought in a variety of diseases, and it wasn't long before the camp was filled with tens of thousands of very sick people.

The British had severe problems when they got to the camp. There were no divisions in reserve in that part of the British Army, so there were no medical personnel to spare. So they had to take care of tens of thousands of sick and dying prisoners with only a handful of doctors, nurses, and medics, plus any other units that could pitch in. One of the division anti-aircraft units supervised the mass burials of the dead and guarded the captured SS guards, who were mostly Hungarian. The British forced the Hungarian SS to bury the dead without protective gear, causing most of them to die of typhus. Eventually the medical personnel were reinforced with medical students from Great Britain and they took over a local hospital (forcing the German doctors and nurses to bathe and care for the prisoners), but over 10,000 prisoners died in the camp after it was liberated. DDT was used widely to disinfect as many people as possible, and it probably saved thousands of lives.

Malnourishment was another major problem. What meager food the prisoners got prior to the arrival of the people from the outlying camps arrived virtually disappeared. The British had dealt with a major famine in India several years before and they tried a few methods for treating malnourishment that had been developed as a result, including nutrient injections. Mostly, these were ineffective and mostly just terrified the prisoners, who had learned during their time in various camps not to trust doctors or really any authority figures. After watching too many prisoners die from overeating (sometimes as little as a single potato or half a loaf of bread was enough to kill a malnourished prisoner), they figured out that slowly increasing food rations was the only method that worked.

Once the whole prisoner population had been evacuated (which took several weeks), the British used a couple of flamethrowers to burn the place to the ground, both for sanitary reasons and a sense of utter disgust.

The camp was filmed pretty widely and became the main symbol for the Holocaust in Britain, as Buchenwald did for the Americans and later Auschwitz became for the world.

EDIT: I found two of the books I drew from. One is Remembering Belsen: Eyewitnesses Record the Liberation by Ben Flanagen and Donald Bloxham. The other is After Daybreak: The Liberation of Bergen-Belsen by Ben Shephard.