BT Group PLC (LON:BT.A) raises prices for broadband customers on standard speed deals by 82% when their contracts end - more than any other UK telecoms firm, according to industry data.
UK price comparison website Uswitch said many telecoms firms raise prices substantially after contracts expire, with BT customers suffering the biggest monthly price hike.
A standard BT broadband package costs about £24.99 per month in a contract but that jumps to £45.49 per month after the contract runs out.
READ: BT's quarterly revenues fall but earnings rise after slashing costs
Sky PLC (LON:SKY) is in second place for largest price rises after contracts end. The out-of-contract price for a Sky unlimited broadband package rises 67% to £30 per month, compared to £18 in a contract.
TalkTalk PLC (LON:TLK) raises prices by 59% to £27 per month from £17 for its unlimited fast broadband package while EE’s unlimited broadband increases by 55% to £31 per month from £20.
On average, standard broadband contracts rise by an average of £152 per year the day after they end. Customers on faster fibre service broadband deals see prices rise by an average of 53% per month after contracts expire.
Uswitch calls on providers to issue effective end of contract notifications
Under new rules by regulator Ofcom that come into effect in 2019, telecoms firms will need to notify customers if they can save money by switching to another deal when their contracts end.
However, Uswitch is concerned that customers may fail to see these notifications if hidden inside monthly statements or online account messages.
Uswitch has called providers to issue “effective end of contract notifications” so consumers know “when to dodge these increased out-of-contract charges”.
"Providers benefit if customers are in the dark about when they could seek out better suited deals," said Uswitch's head of regulation Richard Neudegg.
"Ofcom’s consultation on how to implement these notifications must ensure that crucial information doesn't get buried in the small print of bills, or isn't shown at all. In order to be effective, these end of term warnings need to be clear and concise, and implemented in a timely fashion."