A 13-year-old boy has visited all but two of the 270 London Underground stations in one day in memory of his older brother.

Alasdair Clift, from Wirral, Merseyside, took on the “tube challenge” to raise money for charity Bloodwise after his brother Adam, 17, died from lymphoma in March, and only just ran out of time to complete the whole network.

He began his journey at Chesham station, at the end of the Metropolitan line in Buckinghamshire, at 5.15am on Monday, and finished at Heathrow Terminal 5 station in west London in the early hours of Tuesday morning, having navigated the entire underground network.

Alasdair, who is said to be “fascinated” by transport, has so far received more than £12,000 in donations on his online fundraising page, far exceeding his originaltarget of £100.

Alasdair, left, who is said to be ‘fascinated’ by transport, with Adam. He had originally aimed to raise £100 for charity Bloodwise. Photograph: PA

After spending nearly 20 hours on the tube with his father, Richard Clift, 50, Alasdair arrived at Heathrow to applause from a welcoming party of relatives, tube staff and police officers shortly before 1am.

He said he felt “tired, but proud and happy” of his achievement and the huge support he had received.

“This has been an ambition of mine for a while. In 2013, my brother was diagnosed with lymphoma and unfortunately after many rounds of treatment, he passed away in March. I’ve done this challenge to hopefully give other people a better chance,” he said.

Richard Clift said the kindness shown by fellow travellers