U.S. President Donald Trump backtracked on comments that Britain's public health service should be on the table in future post-Brexit trade talks between the two countries, after Prime Minister Theresa May said some areas might be off-limits.

The National Health Service (NHS) is a cherished institution for many Britons. Created after World War II, it provides a wide range of services ranging from routine consultations to life-saving operations.

"I think everything with a trade deal is on the table," Trump told reporters during a visit to London. "So NHS or anything else, or a lot more than that. But everything will be on the table, absolutely."