Tesla boss Elon Musk has offered to buy Twitter, saying he is the right person to "unlock" the social media platform's "extraordinary potential".

In a surprise announcement, Mr Musk said he would pay $54.20 a share for Twitter.

It recently emerged that Mr Musk was Twitter's biggest shareholder after he built up a large stake in the firm.

He said that if his offer was not accepted "I would need to reconsider my position as a shareholder".

In a filing with the US financial regulator, Mr Musk said: "I invested in Twitter as I believe in its potential to be the platform for free speech around the globe, and I believe free speech is a societal imperative for a functioning democracy.

"However, since making my investment I now realize the company will neither thrive nor serve this societal imperative in its current form. Twitter needs to be transformed as a private company."

He added: "Twitter has extraordinary potential. I will unlock it."