One in three homes bought last year in Slough were purchased as second homes or properties to rent out, according to HMRC data.
Last year 34 per cent of properties sold in Slough were classified as second homes — the highest proportion across England, Wales and Northern Ireland.
About 710 homes in the borough with a combined value of £209 million were purchased in the financial year of 2017/18.
That's despite an extra three per cent stamp duty charge on additional properties, introduced in April 2016 as part of a government effort to deter buy-to-let landlords, property investors and second home owners and to help first time buyers.
Figures show that 56 per cent of the £17m collected from stamp duty in Slough last year came from duty on additional dwellings.
Around 232,000 second homes were bought, with an estimated value of more than £70 billion.
The number bought last year in Slough has increased by 25 per cent since 2016/17, when about 570 second homes were purchased.
The National Housing Federation, which represents housing associations, said it was concerned that if more homes are bought up as second homes then it leaves fewer available for residents and pushes up prices of remaining properties.
The federation is calling for a 'renewed focus' on building more affordable housing.
Slough Borough Council service lead for strategic housing services Colin Moone said: "Second homes which are bought as buy-to-let are generally a good thing as they make available more rental properties to residents in the town.
"There is a shortage of housing in the borough, so the increase in rental properties, providing they meet the standards required for rental, will help to provide more options for house hunters and keep rental prices at a reasonable level.