BT has changed the start time of its evening off-peak period from 6pm to 7pm.
This will affect millions of customers who have signed up to BT's free evening and weekend call plans.
Someone who makes 20 minutes of calls daily between 6pm and 7pm could see their quarterly bill rise by over £80.
Although BT is within its rights to change its prices, many customers are angry at the way it was done.
Those most affected will be on a BT "Evening & Weekend" price plan. BT has about 4.7 million of these customers. Currently these people can make free calls to landlines after 6pm on weekdays. From April the free calls will start an hour later.
Also affected will be those on a BT "Weekend" price plan, which includes another five million people. These customers currently get free calls to landlines from 6pm on a Friday to 6am on a Monday. They will lose an hour on the Friday night, but gain an extra hour on the Monday morning until 7am - although this is arguably less useful.
It could have a significant impact on your bill if you don't change your call plan. If you currently speak for 20 minutes to a friend between 6pm and 7pm every day, it will cost you nothing. But from April that call will cost nearly £1.28 per day. which adds up to over £80 per quarter.
However, BT says that at the same time as changing their terms and conditions it is also offering customers an alternative tariff, which will reduce the extra cost to about £15 a quarter.
BT is contractually within their rights to change its call plans and prices. But there have been many complaints about the way it announced the change - in the fourth paragraph of a letter to customers entitled "Free UK landline calls for three months".
"The most outrageous aspect was that the announcement was in tiny writing buried beneath a heap of good news and hype," BT customer Bob Harris told BBC's Working Lunch.
Another customer, Tony Sell, said: "It really annoys me the way BT always put out notices like these as though they are good for the customer and always hide the price increases in the smaller print towards the end."
In response, BT said: "The fourth paragraph outlined the changes to daytime hours and prices in exactly the same size typeface and prominence as the special offer.
"Customers were alerted to the fourth paragraph's significance with the heading 'Some changes to your BT service'."
The short answer is yes. On Tuesday, BT stated that if a customer can show that they are "significantly disadvantaged" by the change, then they will be permitted to leave their contract even if it still has months left to run.
We understand that if a customer states they are "unhappy" with the change, then they will be allowed to leave - and they will not be asked for lots of evidence about how they will suffer from the change.
BT is likely to do its best to try to persuade you to stay, perhaps by making a new offer. But if you want to leave, you should be able to.
Call BT on their customer service number: 0800 800 150.
Source: BBC News, 10th February 2010
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