LONDON  - Aung San Suu Kyi began a bittersweet return to Britain on Tuesday, during which she will address both houses of parliament and have an emotional family reunion after nearly 25 years in Myanmar. The democracy icon will also meet members of Britain's royal family and PM Cameron during her week-long visit, the longest part of her first trip to Europe since 1988. She visited the London School of Economics and met staff at the BBC Burmese Service on Tuesday, her 67th birthday. In a debate at LSE, she spoke of the difficulties of reform in her homeland, where she spent much of the last 24 years under house arrest, and stressed the importance of the rule of law.

"This is what we all need if we are to really proceed towards democracy," she told the packed audience.

"Unless people see that justice is done and seen to be done, we cannot believe in genuine reform."

She also spoke of the necessity of changing the Myanmar constitution.

"Unless we amend the constitution to harmonise with the aspirations of all of the people in our country we will never be able to bring about the kind of unity and peace that we all desire."

She called for foreign investment in Myanmar and urged that companies plough resources into creating jobs and badly-needed vocational training.

Suu Kyi also said she had been "surprised" and "touched" by the reception she had received on a trip which has also taken in Switzerland, Norway and Ireland.

"During this journey, I have found great warmth and great support among peoples all over the world," she said.

"I think it's all of you, people like you who have given me the strength to continue," she said, "and, I suppose, I do have a stubborn streak in me."

As a special birthday gift, she was given a photograph of her father, independence leader General Aung San, taken on his visit to London in 1947, a few months before he was assassinated.

Her face broke into a broad smile as she held aloft the photograph, which the LSE believes she has never seen before.

Later, she was to attend a family reunion in Oxford, where she studied at the prestigious university and lived for several years with the late Michael Aris, her English husband and father of her two sons.

The Chancellor of Oxford University, former Hong Kong governor Chris Patten, will formally welcome her on Tuesday.

On Wednesday, the university - where she studied politics, philosophy and economics - will award her an honorary doctorate in civil law and she will deliver a speech in the 17th century Sheldonian Theatre.

On Thursday, Suu Kyi is to address both houses of parliament in London, an honour only granted to high-profile foreign dignitaries such as US President Barack Obama.

She will also meet Cameron and heir to the throne Prince Charles and his wife Camilla.

Suu Kyi said at the weekend that she hoped the trip to Oxford would not be "tinged with sadness."

She spent nearly 20 years in the city, and when she left for Myanmar to care for her dying mother in 1988 she had no idea it would be nearly a quarter of a century before she would return.