LONDON (REUTERS, AFP) - Britain's Queen Elizabeth has accepted medical advice to rest for the next few days and has cancelled a planned visit to Northern Ireland, Buckingham Palace said on Wednesday (Oct 20).

The Queen, 95, has reigned for almost seven decades. She was just 25 when she became Queen Elizabeth II on Feb 6, 1952, on the death of her father.

"The Queen has reluctantly accepted medical advice to rest for the next few days," the Palace said.

"Her Majesty is in good spirits and is disappointed that she will no longer be able to visit Northern Ireland, where she had been due to undertake a series of engagements today and tomorrow."

A church service to mark the 100th anniversary of the creation of Northern Ireland is due to take place in border Armagh on Thursday.

The Queen sent her "warmest good wishes to the people of Northern Ireland, and looks forward to visiting in the future", the Palace said.

The Queen, Britain's longest-serving monarch, on Tuesday hosted a reception at Windsor Castle for international business leaders attending a government investment summit. She also received the Japanese and EU ambassadors via video link.

Last week, she was seen for the first time using a walking stick in public.

Just this week, she brushed aside an attempt by a magazine to award her the title of "Oldie of the Year", saying that she felt too young at heart.