Heyman v Pyper: cohabitant's proprietary estoppel claim survives summary judgement bid on kitchen expenditure alone

A cohabitant's proprietary estoppel counterclaim against her late partner's £2.7 million estate will go to trial, but only in narrow form.

In Heyman v Pyper [2026] EWHC 2771 (BP), Deputy Master Dovar refused most of an application by the administratrix for summary judgement under CPR Part 24 and strike out under CPR 3.4(2)(a). He did, however, strike out the defendant's central plea of detrimental reliance.

Background

The deceased died intestate in December 2022 after a relationship of about 36 years with the defendant. Under the intestacy rules, his estate passes to his three sisters, one of whom is the claimant. Most of its value lies in the farm where the couple lived, which was held in his sole name.

The defendant's case was that in 2018, after she sold an inherited flat for about £1.6 million, the deceased told her she need not buy another property because he would ensure her needs were looked after. She invested the proceeds instead. She also relied on spending £77,530 on a kitchen extension at the farm in 2022, and on an unsigned 1989 draft will leaving her 35 per cent of his residuary estate. She learned of that draft only after his death. She counterclaimed for 35 per cent of the net estate.

Assurance

The claimant argued that a promise to look after someone's needs does not relate to identified property, relying on Thorner v Major [2009] UKHL 18 and the contrast with unspecific promises of financial security in Layton v Martin [1986] 2 FLR 227. The defendant relied on Re Basham [1986] 1 WLR 1498, where an estoppel was established over a residuary estate.

The Deputy Master had reservations. Re Basham concerned all the deceased's property, not a sum that varied with need, and he described the 35 per cent figure as a post-death rationalisation. Given that Guest v Guest [2022] UKSC 27 makes the promise the starting point for remedy, defining it clearly matters. Even so, the claim was arguable, and what "being taken care of" meant financially was a matter for trial. Changes in her account did not justify rejecting her evidence at this stage.

Detriment

The claim faltered on detriment. Although detriment is a broad concept under Gillett v Holt [2001] Ch 210, the Deputy Master could not see how buying property instead of investing would have made any material difference. No details of the investments were given. Her own evidence was that she lived on the income from them, and a property would have provided accommodation but not that income. He struck out the plea.

A plea that she took no further steps to protect herself was unparticularised. Her witness evidence could not make up for the defective pleading, and the plea will be struck out unless she applies to amend.

The kitchen expenditure fared better. The Deputy Master doubted that the assurances prompted the work, since she never claimed to expect to inherit the farm and benefited from the kitchen herself. Nonetheless, the court found a real prospect that the assurances made her willing to commit funds to the farm.

Credit claim

A separate "credit" claim for the kitchen, post-death farming and running costs was recast at the hearing as unjust enrichment, but no mistake or other unjust factor was pleaded. The court also found it entirely inconsistent with her reliance on the same matters as founding a farm business tenancy in parallel possession proceedings. It will be struck out unless amended.

Amy Proferes, instructed by BP Collins Solicitors, appeared for the claimant. Edward Hewitt, instructed by Darbys, appeared for the defendant.