North Korean leader Kim Jong-un has sent birthday wishes to Queen Elizabeth on her official birthday via the reclusive nation's second-most powerful official.

The chief of the Presidium of the Supreme Assembly of North Korea Kim Yong-nam conveyed the greetings.

"The message wished the queen good health and happiness and the British people well-being and prosperity," according to the official Pyongyang mouthpiece Korean Central News Agency (KCNA).

The Queen marked her official birthday on 14 June with the usual pomp, pageantry and Trooping of the Colour ceremony at Buckingham Palace.

Analysts say North Korea, one of the most isolated countries in the world, must be in dire need of help for it to send a message to the British Queen.

"North Korea is looking for new friends, while they have also sent officials to London to make money on the stock market and seek development aid," Toshimitsu Shigemura, a professor at Japan's Waseda University and an expert on North Korea, told The Telegraph.

"But there is also real concern in the leadership there that the regime could collapse without China's support, so they are looking for a country that might provide them with political asylum. It is possible that they think Britain might provide that."