The pair are members of Students for a Free Tibet
Two Britons arrested in Beijing over a pro-Tibet protest before the Olympics have arrived back in Britain.
Lucy Fairbrother, 23, from Cambridge, and Iain Thom, 24, from Edinburgh, were deported by Chinese authorities and flown back to London.
Ms Fairbrother said they were deported for disturbing public order after a protest at the Olympic site, but were treated well by Chinese officials.
An Olympics spokesman said the action had been unacceptable and "illegal".
Lucy Fairbrother said they had been treated even-handedly by the Chinese authorities.
"We were taken immediately to a police station and then questioned," she added.
"We were treated fine and one of the reasons we were there is that, obviously, Tibetans couldn't be there in our place - they were refused visas.
"And if anyone in Tibet dared to protest, they'd certainly be treated much more harshly and could face torture and imprisonment for a lot longer."
The protesters scaled a 120ft-high (36.5m) lighting pole early on Wednesday morning and unfurled banners reading "One World, One Dream, Free Tibet" and "Tibet will be free".
Iain Thom said they had known they had been taking a risk but that risk was nothing compared with what would happen to Chinese or Tibetan citizens if they staged a protest.
"I've been a Tibet supporter for a long time and I also like climbing as a hobby," he added.
"I felt that I could use my skills together on this action to make a real difference. The situation in Tibet just now is really critical."
The activists said there action had been worth it - but their job was not done and there would be more protests during the games.
Mr Thom said: "Tibet remains an occupied territory, but I feel like we have achieved part of the step towards improving the situation there for Tibetans - so that those in exile can go back to their homeland and those living in Tibet can live without fear of speaking out, to make the choices they want and to make their calls for justice and freedom like they did in March."
In London, a fellow campaigner held a protest at Tower Bridge to coincide with the one in Beijing on Wednesday.
James Murray, 23, climbed suspension cables to reach a height of 100ft (30m) above the River Thames and unfurled a banner saying: "Beijing 2008: Make Olympic History: Free Tibet."
Ms Fairbrother, a Bristol University graduate, was met at the airport by her mother Linda, a television broadcaster.
Mrs Fairbrother said: "I have done live TV all my life, but I haven't been that nervous since my school exams. It is wonderful to have her back."
Mr Thom's father, Brian, spoke to him on Thursday morning.
He later said: "He was very upbeat when we spoke to him on the phone, and I think he's surprised at just how much of a reaction his actions have caused."
Kerry Brown, an expert on Chinese issues with London-based think tank Chatham House, said the Chinese authorities would be "very nervous, obviously, because of the opening ceremony tomorrow and they don't want to spoil that".
But Dr Brown added that if he was "brutally" honest, most Chinese were less concerned about the situation in Tibet than with their country's economy.
The Olympic torch has travelled 87,000 miles (140,000 km) through six continents since leaving Greece in March.
Its journey has been marked by protests about China's human rights record and its policies in Tibet.
During the month in which the torch began its progress, protests flared in Tibet against Chinese rule before snowballing into the worst unrest in Tibet for 20 years.