John Doyle, Jubilee line general manager for London Underground: said:
“The unions have informed us that they are in dispute with us over what they perceive as a breakdown in industrial relations. We are keen to understand their concerns and so will be meeting with the unions later this week to discuss these issues in greater detail.”
More top news
Google been delving deep into its own data, and has some intriguing answers.
The so-called cycle super highway from Westminster to the Tower of London is one of Johnson's flagship transport projects.
Sunday is expected to be the hottest day, with the mercury due to top 26C in London.