I RECENTLY retired from the NHS after 39 years' service, in management, planning, and public health. I write because I am very concerned about a little-noticed clause in the draft EU withdrawal agreement, which may turn out to be an existential threat to our NHS.

To function well, the NHS needs not only enough skilled staff in every discipline, but a level of demand which is manageable in the future.

We often hear of the threat to the NHS of losing the many workers of EU origin, but not so much about a future influx of patients with high health needs.

Article 18(k) of the draft EU withdrawal agreement states, in respect of UK citizens living in the EU: "The host State may only require Union citizens and United Kingdom nationals to present... evidence that they have sufficient resources for themselves and their family members not to become a burden on the social assistance system of the host State during their period of residence and that they have comprehensive sickness insurance cover in the host State."

Bearing in mind that many UK nationals currently living in the EU are at, or approaching retirement age have with existing ongoing health conditions, it is likely that for them, health insurance will be expensive, unaffordable, or unobtainable.

As written, the draft withdrawal agreement could lead to an influx of returning UK nationals, in declining health, just at the time when the NHS is losing skilled staff in the other direction.

I have been following the Brexit debate closely, but have not heard this real risk being mentioned, let alone addressed.

Lindley Owen