Despite uncertainty over Brexit, some Asian developers, including at least one Singapore property giant, have been doubling down on the small but fast-growing build-to-rent (BtR) market in the United Kingdom that is projected to be worth almost £550 billion (S$849 billion) when it reaches maturity.

Malaysian-listed EcoWorld International - in which Singapore developer GuocoLand holds a strategic stake of 27 per cent - has set its sights on building 10,000 homes within five years, which can be adapted for either the BtR or open-market sale (OMS) schemes, Tan Sri Liew Kee Sin, EcoWorld International executive vice-chairman, told reporters during a press trip to London last month.

Even Singapore property developer City Developments (CDL) expanded into the UK BtR market in March with the acquisition of a freehold site in Leeds that will yield 664 units.

BtR refers to properties (often apartment blocks) which are built primarily for renting households. Unlike traditional buy-to-let properties, BtR properties offer additional amenities and aim to create communities where tenants want to stay for longer periods.

Mr Liew said: "If Brexit is resolved in an amicable way, then we'll concentrate on open-market sales. If not, we will focus on BtR. The proportion of BtR and OMS units will depend on the market, but BtR is here to stay for us.

"We are just a (small) developer in London now, but give us five to 10 years, we are going to grow."

A much newer sector than student housing, the BtR market, which is valued at about £10 billion and provides homes for more than 30,000 households currently, holds good growth potential for developers and investors seeking long-term income streams, according to consultancy Savills.

It forecasts that the BtR market could provide homes for more than 1.7 million households on maturity. At £10 billion, the current value of BtR is less than 1 per cent of total privately rented housing in the UK, which Savills puts at £1.5 trillion.

In 2015, EcoWorld International launched three residential projects valued at £2.19 billion in London, as part of its 75 per cent partnership with UK-based Ballymore Group to form EcoWorld Ballymore.

Two of EcoWorld Ballymore's projects - London City Island (LCI) and Wardian in east London - are around 84 per cent sold. They command average prices of between £800 and £1,200 per sq ft. The other project, Embassy Gardens in Nine Elms, is built around the new United States Embassy in London.

Featuring the Sky Pool - the world's first "floating" swimming pool that stretches between two buildings, at a height of 35m - the project commands premium prices of between £1,400 and £1,500 per sq ft, and is 68 per cent sold.

Mr Liew said there is a shortage of residential properties at Canary Wharf. "We were lucky to be able to sell Wardian together with some other projects way before Brexit hit. We have sold over 84 per cent of the projects here... so we are home free."

EcoWorld saw its third-quarter net profit shoot up by more than four-fold to RM58.73 million (S$19.34 million) from a year ago, due to higher recognition of revenue and profit by the group's joint-venture projects in the UK, following the handover of two LCI residential blocks and the commencement of profit recognition from EcoWorld's BtR sales.

For the BtR segment, the developer now has 1,450 units that are either completed or under construction. "We are targeting to add on another 1,000 units this year and another 2,000 next year," Mr Liew said.

Ms Widya Lestaluhu, head of international residential at JLL Singapore, said international investors accounted for 55 per cent of total real estate investment volumes of £60 billion across the UK in 2017 and last year, rising to 75 per cent in central London last year, as pricing, currency advantages and long-term confidence outweighed political concerns.

But there has been greater caution this year as political tensions intensified, with buyers from the Asia-Pacific accounting for only 5 per cent of total UK real estate investment volumes in the first half this year, compared with 20 per cent last year.

Still, there are exceptions to the rule. A Singapore investor, who bought an 820 sq ft two-bedder in LCI after Brexit hit the headlines, said she was drawn to the lively and youthful vibe of the area, proximity to transport links and the project's design, finishings and facilities.

If anything, the pound's continued weakness made the property a "more attractive buy", said the investor, who only wanted to be known as Ms Gladys.

"We intend to keep the property as a long-term investment and we believe there will still be a demand for property rental as London continues to attract many workers and students," said Ms Gladys, who is in her 50s.

When asked, EcoWorld declined to provide data on how much of its UK property sales came from Singapore-based investors.

But while the main focus of the BtR market has been in London, this is expected to change as more people continue to leave the capital for a better, cheaper standard of living in regional cities such as Manchester, Birmingham and Leeds.

A CDL spokesman said: "We believe sentiment will improve when the Brexit issue is resolved.

"Due to increased labour mobility and the growing popularity of renting, CDL sees strong growth potential for UK's BtR, which is a key part of the government's agenda to solve the UK's housing supply-demand imbalance. Brexit is expected to have limited impact on this sector as demand is mainly driven by local tenants, including young professionals and students.

"The UK is one of CDL's key overseas markets alongside China, Japan and Australia. The short-term uncertainties surrounding Brexit have presented... opportunities to acquire prime assets at good valuations."