See:  http://www.theguardian.com/business/2015/may/04/talktalk-raises-prices-again

and:  http://sales.talktalk.co.uk/pricing/info/pricing-notification

TalkTalk are notifying its customers via email and letter of the changes.

They have confirmed that customers within their minimum contract period – usually 18 months – can leave penalty-free as long as they get in touch to cancel within 30 days of receiving the price increase notice.

Those outside of their minimum contract period can also leave penalty-free as long as they give 30 days' notice.