Coach Brendon McCullum says England are "a lot better" than he thought after they won six out of seven Tests in his first summer in charge.
A nine-wicket win over South Africa gave England a 2-1 series win and their most successful home season since 2004.
"It has been something quite special to be a part of," New Zealander McCullum told BBC Test Match Special.
"There are still big challenges in the next couple of years but for now it has been a pretty successful summer."
McCullum and captain Ben Stokes took over after England had won only one of their previous 17 Tests.
Playing an attractive style of cricket, England beat New Zealand 3-0 and won a rescheduled Test against India before the series triumph over the Proteas.
"I thought English cricket had a lot of talent but it's got a lot more than I thought," said McCullum, the former New Zealand captain.
"I knew these guys were good but they are a lot better than I thought.
"It is a very privileged position to be in to go and help these guys perform. It has been an absolute thrill."
England completed the win over the Proteas early on the fifth morning, effectively the third day after day one was washed out and day two cancelled as a mark of respect to Her Majesty Queen Elizabeth II.
Needing 33 more runs to reach their target of 130, the home side lost Alex Lees lbw for 39, but Zak Crawley remained on 69 not out, his first half-century of the summer and highest Test score at home since 2020.
"Zak will learn a lot from this innings," said McCullum. "We saw what he is capable of achieving.
"This process he's gone through over the last couple of months will hold him in good stead. I'm sure he'll grow and develop from where he is."
England's next Test series is in Pakistan in December, where the conditions will be vastly different from at home.
Whereas the three matches against South Africa have been completed in less than nine days of action, it is likely that attritional cricket will be required in stifling heat.
"It is a very special thing that we have managed to achieve this summer, but it is something that we are going to have to try to continue to do," said captain Stokes.
"When we go to Pakistan we can't live off the fact we have six out of seven games, because it is a completely different challenge.
"We want to continue the form we have shown and the way in which we play, to walk towards the danger of what Pakistan is going to throw at us."
Following a two-Test series in New Zealand in February, England will attempt to regain the Ashes next summer after being heavily beaten 4-0 by Australia down under last winter.
The tourists have not won an Ashes series in the UK since 2001, but came close on their last trip in 2019, a 2-2 draw.
"When you know you've got an Ashes coming up very soon, it's hard not to look at it, especially with how the last Ashes trip went," said Stokes.
"We've got to concentrate on Pakistan, then look to plan for Australia.
"I'm excited by the Ashes next summer, especially with the way in which we're playing."
-BBC