Sir David, who is in charge of health services across England and Wales, met staff and patients as he inspected hospital facilities, including the new Acute Admissions Unit (AAU).
He told the Watford Observer that he had been greatly impressed by what he saw.
He said: “I came about 18 months ago and I couldn’t imagine the kind of change that there has been since.
“Most of the good practices that I see demonstrated up and down the country can be found here at Watford General. Patients get a top drawer service.”
Asked about the Health Campus Project, which includes a £300million new hospital development, Sir David reaffirmed his support to it – provided the costs could be met.
He said: "The trust [West Hertfordshire Hospitals NHS Trust] is committed to making it happen. The question will be how long it takes but everyone wants to make it a reality. It makes sense to patients and the NHS.
“The issue is affordability and at what stage we could do it by. But I am hopeful. We still think it is affordable. This Government is committed to it and Andrew Lansley [Conservative MP and health spokesman] who visited the other week said a new Conservative government, if there is one, is committed to it as well.”
Sir David also defended the trust’s controversial decision to shift acute service from Hemel Hempstead to Watford. After meeting two patients, from Bovingdon and the town itself who both received life-saving treatment in Watford in the summer, he said: “It is important to get patients to the right place to be seen by the right medical teams as quickly as possible. “The motivation for the hospitals changing systems was about improving quality. These are brilliant examples of how that has worked.”