How much is 10 Downing Street actually worth?

It’s the most photographed front door in British politics, but nobody’s ever bought 10 Downing Street on the open market. That doesn’t mean we can’t estimate what it would fetch. Using Land Registry transaction data, comparable sales in Westminster, and the open for offer AI valuation model, here’s our best estimate.

The property

Despite its modest Georgian terrace exterior, Number 10 is deceptively large. Behind that famous black door lie approximately 100 rooms spread across three interconnected townhouses. The complex includes private apartments on the upper floors, the Cabinet Room, multiple state reception rooms, a garden, and — yes — a rather nice kitchen.

Total estimated floor area: approximately 21,000 sq ft. Grade I listed. Freehold (Crown Estate). Leasehold to the Prime Minister at a peppercorn rent.

Our valuation

Comparable evidence in SW1A is thin on the ground for obvious reasons, but recent transactions in Westminster give us benchmarks:

• Average price per sq ft in SW1A: £2,400–£3,200
• Premium for historical significance: +40–60%
• Discount for Grade I listing restrictions: -15–20%
• Trophy value / irreplaceability premium: +100–200%

Our AI valuation estimate: £54.5 million

Confidence interval: £42m–£68m. The wide range reflects the genuinely unique nature of the property — there are no true comparables.

What would the mortgage be?

At a 4.2% rate with 25% deposit (£13.6m), your monthly payment on a 25-year repayment mortgage would be approximately £221,000. Per month. That’s before council tax (Band H in Westminster: £1,886/year — surprisingly affordable relative to the property).

Make your fantasy offer

Think you know better? We’ve added 10 Downing Street to our Famous Properties collection. Make your fantasy offer and see how you compare against other open for offer users.