By Jonathan Davies

Twitter chief executive Dick Costolo is stepping down, the social media giant has announced.

Mr Costolo will leave at the end of the month, with co-founder Jack Dorsey taking over on 1 July until a replacement can be found.

The outgoing boss has been under huge pressure over the past year with shareholders unhappy over slow user growth and profitability.

In April, Twitter announced an annual loss of $162m (£104m) and missed market expectations for revenues. Twitter's share price has fallen 30% since, but rose 7% after the news of Mr Costolo's departure.

Mr Costolo said in a statement: "I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the company."