Britain knows what its Brexit deal would look like, but not whether that deal will be approved by Parliament. And continued uncertainty about the manner of the country’s departure from the EU appears to be having an effect on the U.K. property investment market.

In spite of some huge deals, U.K. investment volumes for the third quarter fell by 27% compared to the same period last year, according to Datscha, the PropTech platform which shows ultimate ownership of commercial properties. Volumes in Q3 were £12.7B compared to £17.4B in Q3 2017.

Quarterly volumes have steadily dropped in 2018, from £19.6B in the first quarter, then £16.2B in the second, and down again in the third. And there is no sign of this trend being reversed.

“Already in Q4 to date, commercial property transaction volumes (over £3M) are around 10% lower than last year,” Datscha Head of Research Lesley Males said. “This is being driven by factors such as investors’ reluctance to invest in the U.K. retail sector as well as overseas investors potentially delaying investments until the U.K. leaves the EU next year.”

London was more robust but still saw a 4% fall compared to Q3 last year, £7B compared to £7.3B.

These falls were in spite of some huge transactions being completed during the period. The £1.2B purchase of Goldman Sachs’ new City of London HQ by Korea’s National Pension Service is one of the largest single-asset deals in U.K. history. Blackstone and Telereal Trillium’s £1.4B purchase of a portfolio of railway arches from Network Rail is one of the largest portfolio deals in recent years.

London is still being dominated by overseas investors, and 90% of deals in the City were undertaken by foreign buyers. Other significant London deals included the purchase of the Adelphi building from Blackstone by Amancio Ortega’s Pontegadea for £650M and Deka’s purchase of the Verde building from Tishman Speyer for £460M. Both buildings are in the West End, which was the district which saw the largest amount of deals, 29% of London’s total.

The tough climate for retail property was highlighted by the fact that transactions in the sector fell 44% compared to last year, from £3.4B to £1.9B. And industrial transactions of £1.9B put that sector on par with retail, which used to vie with offices for the top spot.

The largest retail deal was the £175M purchase by Korean firm Hana Financial of Gallagher Retail Park in the West Midlands, and the next largest was the sale of two retail parks in Bristol and Kircaldy to a Japanese investor for £164M.

Investment in rented residential totalled £1.15B, with the £400M forward-funding deal of two schemes in Barking and Kew by EcoWorld and Invesco the largest transaction.

That London investment volumes remained relatively stable while the U.K. overall dropped gives lie to the theory that it is London’s property market which will suffer most as a result of Brexit. Investment volumes outside of the capital fell 44% to £5.7B, and £1.25B of this was in the South East. London remains highly liquid compared to the rest of the country.