The UK government announced on Sunday early stage plans to erect a permanent memorial to the late Queen Elizabeth II, alongside a national legacy programme in her honour, in 2026.

The "fitting tribute" to Britain's longest-reigning monarch, who died in September last year aged 96 after 70 years on the throne, will be unveiled to coincide with what would have been her 100th birthday.

A newly-formed entity -- the Queen Elizabeth memorial committee -- will consider and recommend proposals for the memorial and legacy programme, government department the Cabinet Office said.

The independent body -- to be headed by Robin Janvrin, the late sovereign's former private secretary -- will consider her life, decades of public service and the causes she supported, it added.

Janvrin, a member of parliament's unelected House of Lords chamber, called his appointment "an honour".

"It will be a unique challenge to try to capture for future generations Her Late Majesty's extraordinary contribution to our national life throughout her very long reign," he added.

Senior royal, political and other figures and experts are set to be appointed to the committee to develop ideas and bring their recommendations to her heir, King Charles III, and Prime Minister Rishi Sunak.

The committee will also seek suggestions from the public during the preparatory process.

The government said it will support the proposals and consider funding options.

"Queen Elizabeth II was our longest reigning monarch and greatest public servant," Deputy Prime Minister Oliver Dowden said.

"Lord Janvrin will now begin the important work of designing a fitting tribute to her legacy of service to our nation and the Commonwealth."