Islamabad, Apr 18 (IANS): Former Pakistan Prime Minister Nawaz Sharif and his daughter Maryam left for London on Wednesday and vowed to return before the next accountability hearing.

They former leader and h=is daughter are scheduled to return on April 22, reports Dawn news.

However, in a tweet just before their departure, Maryam vowed to return before the next hearing if they were not granted an exemption from appearance by an accountability court where proceedings over the family's London properties was underway.

"My mother is hospitalised again," she had tweeted a day earlier after the family had issued a statement informing that the two would leave for London to see the ailing Kulsoom Nawaz.

Kulsoom Nawaz had undergone a surgery for lymphoma (throat cancer). The Pakistan Muslim League-Nawaz (PML-N) had declared the procedure successful, but of late her condition has deteriorated.

Last week, the PML-N government had shown reluctance to place the names of Nawaz Sharif, his children -- Maryam, Hassan, and Hussain -- and his son-in-law retired Captain Safdar on the Exit Control List (ECL) on the request of the National Accountability Bureau (NAB), reports Dawn news.

All of them are being tried in accountability courts regarding references filed following the Supreme Court's orders in Panamagate case.

Sharif's sons are already in London and have been declared proclaimed offenders by the accountability court in the corruption references against them.