Ugandan opposition leader Kizza Besigye, whose return to Kampala last week drew crowds that dwarfed President Yoweri Museveni’s on his own inauguration day, is under “house arrest” according to his party officials.

Besigye has been leading a series of walk-to-work protests that have presented the biggest challenge yet to Museveni’s 25-year rule. The marches have been held every Monday and Thursday since April but this morning Besigye decided not to walk, claiming a bad case of flu.

Instead his wife Winnie Byanyima, a former girlfriend of Museveni, drove out in the family car only to find herself picked up by police who have blockaded his house and towed to a nearby police station. She was later released.

Officials from Besigye’s Forum for Democratic Change party said their leader is now under house arrest.