Three of Britain’s biggest power firms are reserving their cheapest deals for customers who agree to have a digital smart meter installed in their home.

It means that loyal British Gas, EDF Energy and First Utility customers who do not want the new technology are being denied savings of up to £111 a year.

Another supplier, E.ON is forcing customers who sign up to its deals to agree to being contacted about smart meters at any time.

Experts say suppliers have started using smart meter-only tariffs as the latest tactic to pressure customers into changing their meters.

Loyal British Gas, EDF Energy and First Utility customers who do not want smart meters in their homes are being denied savings of up to £111 a year

Suppliers have been told by the Government to try to install smart meters in all the UK’s 50 million homes and businesses by the end of 2020. If they fail to do enough, they face fines of up to £7 billion.

However, customers can refuse to have the new technology, and suppliers are becoming desperate to persuade more people to sign up.

Last week, as part of Money Mail’s Stop The Smart Meter Bullying campaign, we handed the energy watchdog a dossier of damning complaints about the bullying tactics suppliers are using to get homeowners to install smart meters.

We revealed that firms were misleading customers into thinking the new meters are a legal requirement, and bombarding households with calls and texts even after they have said they don’t want one.

Now, it has emerged that providers are locking loyal customers out of their best deals.

First Utility’s cheapest tariff costs the average family £906 a year, according to figures from comparison site Energyhelpline.

But it is available only to people who agree to have a smart meter installed within six months of signing up. If you do not get a smart meter in this timeframe, you will be charged an exit fee of up to £60 and moved onto a different tariff.

They will then be offered First Utility’s next best deal, currently £111 more expensive at £1,017.

Anyone who already has a smart meter in their home is barred altogether from signing up to the firm’s Smart First June 2019 tariff.

At British Gas and EDF Energy, customers can only get the best deals if they have a smart meter or agree to have one installed.

Suppliers have been told by the Government to try to install smart meters in all the UK’s 50 million homes and businesses by the end of 2020

The cheapest tariff on offer to British Gas customers with old meters is HomeEnergy Secure Apr 2020 at £1,126 a year for the average family.

This is £71 more expensive than their smart meter deal, HomeEnergy Plus Cover May 2019, at £1,197.

British Gas’s FreeTime energy tariff — which includes eight hours of free energy each Saturday, and which is said to save customers around £60 a year — is also reserved for households with smart meters.

EDF Energy customers without smart meters pay £1,065 a year on its Blue Price Protection tariff — £65 more than homeowners with smart meters on its Easy Online May19 plan at £1,000.

Meanwhile, E.ON includes a clause in the small print of its six dual-fuel tariffs that says: ‘We may contact you at any time to offer you a smart meter.’

E.ON customers have sent reams of evidence to Money Mail showing how the firm has bombarded them with letters and emails about smart meters. This clause appears to give the company the green light to ignore your complaints.

SSE offers two deals at £1,108 but only one of them — Fix & Shop Paperless Billing — requires customers to give permission to be contacted about the rollout.

‘You are registering your interest for a Smart Meter. This means we may contact you in the future to discuss a smart meter installation as and when you become eligible,’ it says.

Reader Stuart Cunningham received a letter from SSE saying he needed to show an interest in having a smart meter installed to switch to its cheapest tariff. ‘It smacks of coercion, and energy providers shouldn’t be allowed to act in such an underhand way,’ he says.

Martyn James, of the complaints website Resolver, says: ‘Smart meters once promised to be the great hope for householders wanting to reduce their bills. But their introduction has been marred by bully-boy businesses pressuring people to take them out, technical troubles, and confusion about whether they’re worth having.

‘Offering incentives to people who take out smart meters is fine — as long as it doesn’t create a two-tier system where older and more vulnerable people once again pay the price for not switching.’

An EDF Energy spokeswoman said: ‘We are trialling a number of ways to encourage customers to have a smart meter installed, and including the opportunity in one of our most competitively priced tariffs is just one of them.’

A spokesman for First Utility says: ‘As part of the Government roll-out, we are looking at a number of ways to engage customers who don’t have a smart meter yet, and this offer is about helping to do that. We make it clear when customers are free to change their mind.’

An E.ON spokesman said: ‘If customers do not want a smart meter, they can contact us.’

A spokesman for SSE said: ‘Customers are not obliged to have a smart meter installed. If a customer tells us they don’t want to receive communications relating to smart meters then we will flag this in our customer database.

The clause in the contract is the equivalent of marketing consent, a common practice in most sectors.’

Robert Cheesewright, of Smart Energy GB, which promotes the roll-out, says: ‘It’s a win-win situation if you can get a cheaper tariff and a smart meter at the same time.’

A spokesman for British Gas declined to comment.

s.smyth@dailymail.co.uk