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Japanese Knotweed in Greater London

A comprehensive Japanese knotweed risk assessment for Greater London in the London region — covering local risk factors, affected areas, and practical advice for homeowners, buyers, and sellers.

Knotweed Risk in Greater London

Greater London has significant knotweed risk across all boroughs. The extensive Victorian and Edwardian housing stock, Thames tributaries (Lea, Wandle, Ravensbourne, Brent), and one of the world's densest railway networks all contribute. South London boroughs along the railway corridors from Waterloo and Victoria are particularly affected. Garden waste disposal, fly-tipping, and construction soil movement ensure continued spread across the capital.

What to Do If You Find Knotweed in Greater London

If you discover or suspect Japanese knotweed on a property in Greater London:

  1. Don't disturb it — Cutting, mowing, or digging can fragment rhizomes and worsen the infestation
  2. Get a professional survey — A PCA-accredited surveyor will confirm identification, categorise the infestation, and recommend treatment
  3. Start treatment promptly — Early intervention limits spread and reduces long-term costs
  4. Obtain an insurance-backed guarantee — Essential for property transactions and mortgage applications
  5. Know your legal obligations — You must prevent knotweed from spreading to neighbouring properties

If you're buying in Greater London

Properties in Greater London should be checked for knotweed as part of the buying process. A standard homebuyer's survey may note knotweed but won't provide the specialist assessment needed for mortgage approval. Commission a dedicated knotweed survey alongside your standard survey.

If you're selling a property in Greater London and know about knotweed, proactive treatment and documentation will help your sale proceed smoothly.

Areas in Greater London

Browse knotweed information for specific areas within Greater London:

Wandsworth

SW11, SW15, SW17, SW18

Ealing

W5, W7, W13, UB1, UB2, UB5, UB6

Hounslow

TW3, TW4, TW5, TW7, TW8, W4

Richmond upon Thames

TW1, TW2, TW9, TW10, TW11, TW12, SW13, SW14

Croydon

CR0, CR2, CR7, CR8, SE25

Bromley

BR1, BR2, BR3, BR4, BR5, BR6, BR7

Lewisham

SE4, SE6, SE8, SE12, SE13, SE14, SE23, SE26

Greenwich

SE3, SE7, SE9, SE10, SE18, DA16

Hackney

E5, E8, E9, N1, N4, N16

Islington

N1, N5, N7, N19, EC1

Camden

NW1, NW3, NW5, NW6, WC1, WC2

Lambeth

SE1, SE5, SE11, SE24, SE27, SW2, SW4, SW8, SW9, SW16

Southwark

SE1, SE5, SE15, SE16, SE17, SE21, SE22, SE24

Tower Hamlets

E1, E2, E3, E14

Newham

E6, E7, E12, E13, E15, E16

Barnet

N2, N3, N11, N12, N20, NW4, NW7, NW9, NW11, EN4, EN5

Haringey

N4, N6, N8, N10, N15, N17, N22

Enfield

EN1, EN2, EN3, N9, N13, N14, N21

Brent

NW2, NW6, NW9, NW10, HA0, HA3, HA9

Hillingdon

UB3, UB4, UB7, UB8, UB9, UB10, UB11

Kingston upon Thames

KT1, KT2, KT3, KT5, KT6, KT9

Merton

SW19, SW20, CR4, SM4

Sutton

SM1, SM2, SM3, SM5, SM6

Waltham Forest

E4, E10, E11, E17

Redbridge

IG1, IG2, IG3, IG4, IG5, IG6, IG7, IG8

Havering

RM1, RM2, RM3, RM5, RM6, RM7, RM11, RM12, RM13, RM14

Bexley

DA5, DA6, DA7, DA8, DA14, DA15, DA16, DA17, DA18

Westminster

W1, W2, W9, W10, W11, SW1, NW8, WC2

Kensington and Chelsea

W8, W10, W11, W14, SW3, SW5, SW7, SW10

Hammersmith and Fulham

W6, W12, W14, SW6

Frequently Asked Questions

How common is Japanese knotweed in Greater London?
Greater London has significant knotweed risk across all boroughs. The extensive Victorian and Edwardian housing stock, Thames tributaries (Lea, Wandle, Ravensbourne, Brent), and one of the world's densest railway networks all contribute. South London boroughs along the railway corridors from Waterloo and Victoria are particularly affected. Garden waste disposal, fly-tipping, and construction soil movement ensure continued spread across the capital.
Should I get a knotweed survey when buying in Greater London?
If you're buying a property in Greater London, a specialist knotweed survey is recommended — particularly for older properties, those near waterways or railway lines, and any property where the seller has indicated knotweed on the TA6 form. A PCA-accredited surveyor familiar with Greater London will understand local risk factors and can provide a RICS-compatible report for your mortgage lender.
How much does knotweed treatment cost in Greater London?
Treatment costs in Greater London are broadly in line with national averages: £2,000–£5,000 for herbicide programmes and £10,000–£50,000+ for excavation. Costs may be slightly lower in high-density areas where treatment companies are more established and competitive. Always get at least two quotes from PCA-accredited companies.
Can I get a mortgage on a property with knotweed in Greater London?
Yes, most mainstream lenders will approve mortgages on Greater London properties with knotweed, provided a treatment plan and insurance-backed guarantee are in place. The RICS management category assigned by your surveyor determines which lenders will proceed. See our mortgage guide for lender-specific policies.