Build More, Charge More: How London's Construction Boom Is Reshaping the Rental Market

The Greater London Authority granted planning consent for 34,700 new homes in the 12 months to March 2026, the highest annual figure since Sadiq Khan's first term — yet average asking rents across the capital hit £2,650 per month in June, up 6.4 percent on the same month last year. The pipeline is growing. The relief is not here yet.

That gap between permissions granted and keys handed over matters enormously right now. The stamp duty reform that came into force in January — restoring the old buy-to-let surcharge threshold and introducing a new small landlord relief for portfolios under five properties — has begun pulling cautious investors back into the market after two years on the sidelines. But cautious is the operative word. New supply from the planning consents of 2025 won't translate into lettable units before late 2027 at the earliest for most major schemes, leaving tenants in an awkward limbo between a tightening market today and the theoretical abundance of tomorrow.

Where the Pressure Is Sharpest

Nowhere illustrates the squeeze more starkly than East London's Stratford and the Royal Docks corridor. Lendlease's Smithfield London scheme at the former Thamesmead industrial site, which received revised consent from the London Borough of Newham in April, will eventually deliver 4,800 homes, roughly 35 percent of them at London Affordable Rent. But construction mobilisation isn't expected until the first quarter of 2027, meaning every tenant currently competing for a two-bedroom flat in E16 or E20 is doing so in a market with almost no new stock this summer.

In South London, the picture is similar. Peabody's regeneration of the Thamesmead Waterfront — a 11,500-home masterplan stretching along the SE28 shoreline — has secured phased consents through 2025 and into early 2026, but Phase 1 completions are pencilled in for 2028. Letting agents along Woolwich High Street reported in May that the average void period for a rental property fell below six days, meaning new listings are being snapped up before most prospective tenants even see them advertised.

Inner zones aren't immune. In Bermondsey, one-bedroom flats on Tower Bridge Road are now routinely listed at £2,100 per month, a figure that would have been considered aggressive two years ago. Transport for London's latest data shows Bermondsey station saw a 19 percent rise in annual entries and exits following full Elizabeth Line integration — that commuter convenience premium has fully migrated from sale prices into rental valuations.

Landlords Do the Maths Again

The January stamp duty changes have measurably shifted sentiment among smaller landlords. Figures from Rightmove show London landlord listings rose 11 percent in the first quarter of 2026 compared to Q1 2025, the first sustained increase since 2022. Yet mortgage costs remain punishing. A standard buy-to-let product on a £400,000 property in Zone 3 is still being priced at between 4.8 and 5.3 percent, according to broker data published by London & Country Mortgages in June, which means gross yields of less than 5 percent — common in Zones 1 and 2 — remain borderline unviable without significant capital growth assumptions baked in.

The boroughs where returns pencil out most clearly are those along the Zone 4-6 corridor: Romford, Sutton, and Walthamstow are drawing the most activity from landlords re-entering the market, according to the National Residential Landlords Association's London chapter. Average two-bedroom rents in Walthamstow E17 are now £1,720 per month, up from £1,490 in June 2024 — a 15.4 percent rise that has outpaced wage growth in almost every sector of the London economy.

For tenants, the practical reality heading into the second half of 2026 is grim but not static. Renters' rights advocates at Shelter's London office point to the Renters' Rights Act, which received Royal Assent in March, as a meaningful floor under tenant protections — abolishing Section 21 no-fault evictions means those who hold a tenancy have more security than at any point in the past decade. The pressure is at the point of entry, not during a tenancy. Anyone already in a flat in Peckham or Hackney should think very carefully before moving. Anyone looking to rent for the first time this summer should be prepared to act within hours of a viewing, carry references already assembled, and budget for rents roughly 8 to 10 percent above what Zoopla listings showed six months ago.