When the Royal Dockyard in Chatham closed in 1984, former marshland St Mary’s Island was an uninspiring piece of brownfield dirt.

Today, the 150-acre site is the location of about 1,700 modern homes developed since the late 1990s by Countryside and the Homes and Communities Agency (HCA).

The transformation of the ancient site is the longest-standing project in the county for Countryside, which is about to enter another long-term partnership with the HCA on the 1,400-home Rochester Riverside redevelopment, estimated to cost £400 million.

The Essex-headquartered company, which rejoined the London Stock Exchange last year after 11 years of private ownership, expects to build and sell about 500 homes a year in Kent over the next five years.

Yet this flurry of activity was not possible a few years ago, as the housebuilding sector recovered from the recession.

Countryside built just 26 homes in Kent in 2014, against 2,044 nationally. In its latest financial year, that county figure reached 401, with 3,389 built across the UK.

Iain McPherson, the managing director of its south division, based in Sevenoaks, said: “During the recession we found a lot of money being restricted by the banks and investment into the development community was reduced.

“Also, a lot of people left the industry as a result of it contracting. As the market started to improve in 2013, getting hold of people to assist in the expansion has taken time.”

Those days appear to be over, for now, as Mr McPherson estimates 70% of Countryside’s development activity will be in Kent next year.

This will increase the amount spent in the supply chain in the county to about £30 million, nearly doubling the £38 million spend on Kent-based suppliers in the past five years.

Yet there are still many challenges facing the housebuilding community, despite the government’s drive to increase construction of homes across the county.

“Many things need to be there at a macro level,” said Mr McPherson.

“You need a good level of employment for people to be able to buy. Finance needs to be in place from the banks and other lending institutions.

“There have been some supply-side issues in recent years with the availability of labour and what might happen after leaving the EU.

“We did a straw poll of all our developments in Kent and 30% of our workforce in the county are from the EU. That could have an impact.”

The recent increase in interest rates by a quarter percent to 0.5% “is only reversing the decision made last year” when they dropped to 0.25%.

Although the company is “mindful” of any changes, and whether it affects affordability of mortgages, “the medium to long-term position is unaffected”.

Countryside, which employs about 150 people in the county, is building on 12 sites in Kent, which will reach 16 by the end of the year.

All of these are in the west of the county, where house prices are significantly higher than the east.

Mr McPherson said: “Countryside isn’t a low-cost, volume housebuilder. That is not our business model.

“We are more about developing homes which are high-quality and masterplanned. We spend a lot of time and money in bespoking developments, which adds a cost to development.

“If prices are lower then sometimes you aren’t always able to recover that cost because it’s unlikely people can pay it.”

He added the firm’s land strategy aimed to “start development near the office” in Sevenoaks, which was opened in 2015.

He said: “It has been a stepping stone. The strategy has been large sites along a transport corridor, which is economical.

“We are looking at developing along the A2 corridor towards Canterbury and the M20 towards Ashford. We started at the M25 and are working our way down.

“It has been about doing it in a sensible fashion. There is no point having a site in east Kent when you don’t have anything else around it.

“We want to make sure we have got staff living in and around our development. We are slowly moving out that way but it will take a couple of years. We are buying towards the east.

“We do have some sites further east but these are confidential at the moment.”

He added: “In east Kent, demand is pretty good and the best it has been in a decade, and the county council strategy towards investment in infrastructure is definitely helping.

“HS1 is also unlocking perceptions of living in east Kent, which has not been there previously.

“It’s more acceptable for buyers to consider a seaside home with the option of working in Kent or London. You can move there now and get around more freely than you have been able to previously.

“For us, it’s about a sensible plan for development.”