The north-west of England the best place to invest in buy-to-let properties across England and Wales, according to property expert One and Only Pro.

The online property portal used its unique algorithm to rank the top 172 buy-to-let locations in the UK, giving investment properties a score of one to 10 based on their likelihood to increase in value.

Analysis found the five locations with the highest-concentration of top-scoring properties – dubbed “diamond property hotspots” – are all in the north-west of England.

At the top of the list, Salford, just outside Manchester, boasted 21% of properties showing the greatest investment potential. Properties in this area given the top score by One and Only Pro included a three-bedroom flat priced at £130,000 ($168,140), with a 12% potential yield and expected rental income of £1,000 ($1,300) per month.

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Burnley in Lancashire came in second with 20% of properties showing the most investment potential, while Birkenhead and Bootle, both just outside Liverpool, shared third place with 16%. The seaside resort of Blackpool took the last spot in the top five with 12%.

These “satellite towns,” with high deprivation levels and broadly low house prices, are expected to increase in popularity due to big city neighbourhoods being “overbought in comparison,” according to One and Only Pro.

Despite the top five hotspots being located in the north-west, there are still “diamonds” to be found all across the nation. One of these is a flat in north London that boasts an 11.65% potential yield, according to One and Only Pro.

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Henri Sant-Cassia, CEO of One and Only Pro, said: “It is true that the north-west is showing the greatest number of properties with investment potential, but a shrewd investor can find ‘diamonds’ almost anywhere in the UK.

“The top location in Wales, for example, was Swansea in position 28 out of 172, and Portsmouth comes in 32nd place, claiming the top spot for the south of England. There are also 2% of properties on the market in London – in 60th position on the list – that will see an increase in value and represent a solid investment.”

One and Only Pro has noted that it only lists properties considered to be viable for investment, so shared ownership, retirement and other “unsuitable” property types have been stripped out of the data. Everything listed has been pre-vetted for investment, “unlike a typical property portal where the whole market is on show.”