The Duke is a pub that does a lot of things right, but the reason it's a pub worth mentioning among London's many hundreds of pubs is that it serves food that's well above pub grub standards.
That could be because half of it's laid out as a restaurant proper; it could also be because The Duke, like other local pubs, sources local products, and Richmond is close to Britain's kitchen garden so closer to the source. But the reason's not important is it. It's what they make out of the local, seasonal produce that matters. And they combine it into dishes you could refer to on a menu as 'Modern British Fare': venison sausages and mash, half a baked Butternut squash stuffed with wild mushrooms and Stilton, rib of beef, salmon cooked in parcels... Ok, so the salmon parcels aren't particularly British, but they're deliciously done - wrapped with their veggies and seasoning in their parcels of greaseproof paper - and have become the lighter staple on these sorts of menus.
The food is good but that's partly because it's good value. The wine list also benefits from the onsite restaurant, but that's probably not the reason for the selection of great ales on tap – that's probably just because they're a pub and they like ale...
The décor is slightly puritanical: white walls and dark wood, but there's lots of natural light coming in, so it's probably more Mayflower than Mormon Country.