In May 2018, Ruth sold a freehold building which she had used exclusively for business purposes. The building was sold for £350,000, realising a chargeable gain of £92,500.

In June 2018, she bought fixed plant for £400,000 and elected to hold-over the gain on the building against this plant. In August 2023, she bought another freehold building for £335,000 and elected to transfer the held-over gain to this new building.

Explain the treatment of the £92,500 gain.