Research complied by Which? placed Nationwide, Skipton and Yorkshire Building Society (YBS) as the top three.
The the former two both scored 78 per cent with YBS placing third with 75 per cent.
All three of the lenders scored a full five stars for customer service and transparency of charges, and were also the highest scorers when it came to flexibility of payments, each with four stars.
To become a WRP, mortgage lenders must have achieved a customer score of 70 per cent or over.
They also need to consistently offer table-topping mortgage deals across a range of product types, and be fully covered by the Financial Services Compensation Scheme (FSCS) and Financial Conduct Authority (FCA) banking standards scheme.
The consumer champion questioned over 3,400 Brits for the survey, with each provider receiving a customer score.
Other providers that fared well included Accord Mortgages, Santander and TSB who were the fourth and joint fifth ranked lenders with scores of 72 per cent and 71 per cent respectively.
Coventry Building Society and NatWest also performed well, both reaching 70 per cent in the survey.
High street banks slip away
The Which? survey revealed that high street banks had fallen down the rankings. Barclays and HSBC both received customer scores of 65 per cent with Halifax on 64 per cent.
None of the firms managed to score more than three out of five stars across categories including clarity of statements and flexibility of payments.
Meanwhile, Family Building Society, Kensington, Metro Bank and The Co-operative Bank for Intermediaries all finished towards the bottom of the Which? table with scores in the mid-50s.
The key differentiator between the small providers and their big name rivals was that they could cater to more specific situations, such as for first-time buyers with smaller deposits or for those who are self employed. This is despite the bigger names being able to offer a more extensive range of products.
‘Customer service more important than ever’
Ele Clark, the senior money editor at Which?, said: “With mortgage rates at some of their highest levels for 15 years and alarming numbers of homeowners struggling to meet their monthly payments, customer service is more important than ever. Our research has found that some of the UK’s biggest building societies lead the way when it comes to quality service, with greater transparency over charges and, crucially, flexibility when making payments.
“The FCA has now set higher standards in its Consumer Duty, raising the bar for customer service, and firms that fail to meet that bar should expect to face tough consequences from the regulator.”
