Energy supplier Bulb has scrapped its popular refer a friend scheme as it tries to raise new cash amid energy sector turbulence which has seen many of its rivals go bust.

The scheme had been running for several years and promised users £50 of credit if one of their friends joined, and would also pay £50 to the friend.

The scheme was still live on Bulb’s website earlier this week, but has now been taken down.

“While wholesale energy prices are so high, we’re temporarily pausing our referral scheme where we reward members for signing up their friends and family. We love to pay our members for spreading the word about Bulb, so we’ll bring it back as soon as we’re able to,” the company said after being approached by the PA news agency.

Rival supplier Ovo has also changed its website to make it more complicated for new customers to join, as more than 1.5 million customers have seen their energy supplier collapse this month amid surging wholesale gas prices.

Ovo Energy has taken down a box from its site which allowed customers to “get an energy quote in under 2 minutes”.

Customers can still get through to sign up with Ovo, but the process is now more complicated than before.

One industry insider speculated that the company might be trying to slow the flow of new customers who are abandoning less stable small suppliers in favour of the larger players.

Companies would normally welcome new customers with open arms, but amid runaway gas prices it has become very expensive to bring in new households.

On Thursday the collapse of suppliers Avro Energy and Green Supplier Limited meant that so far this month around 1.5 million households have seen their energy provider go out of business.

Regulator Ofgem has processes to ensure that these customers are moved to new suppliers so their gas and electricity will not be cut off.

Experts worry however that Ofgem’s so-called Supplier of Last Resort scheme will struggle to deal with the sheer number of customers that will now need to go through the process.

Last weekend the Financial Times reported that Bulb, which has around 1.7 million customers, is trying to secure new funds from investors amid the crisis in the sector.

At the time Bulb told the paper that “from time to time we explore various opportunities to fund our business plans and further our mission to lower bills and lower CO2”.

It added: “Like everyone in the industry, we’re monitoring wholesale prices and their impact on our business.”