It’s the scourge of the 21st century. Dementia cannot be reversed. In the face of this diagnosis and relatives or friends eclipsed by the disease, we feel impotent. We want to do something.

The message from this Brighton and Sussex Medical School-organised debate was: we can. It landed - there was a distinct energy in the room afterwards.

Clueing up on dementia includes revising your expectations of life, as theatre director Matthew Lenton did, parenting a daughter he would never take for swimming lessons.

At the end of his career, former Vice Admiral Sir Peter Woodhead looks after his wife and her sister at home. He knows now that friends who make vague offers to help just need to know what they can usefully do.

Professor Sube Banerjee (National Dementia Strategy author) explained that 800,000 families in our midst are dealing with the consequences of dementia as loved ones become vulnerable and dependent strangers and - a cruel symptom - often no longer recognise spouses, partners, adult children who care for them.

Ethicist Bobbie Farsides, was absolutely clear: we need to broaden our view of life to include dementia as a possible future. Articulating wishes, concerns and preferences now may guide future carers.