Property firm Land Securities has reported an 8.8 per cent slide in the value of its portfolio, but said it was outperforming industry benchmarks and its planned demerger was progressing well.

The UK's largest commercial real estate firm – one of three partners in the Birmingham Alliance, which built and owns the Bullring – said the value of its largely office and retail properties fell £1.28 billion in the year ended March 31 to £13.58 billion.

"The market is demanding but we have performed well in relative terms this year and our results show considerable success in terms of value preservation in the face of a sharply falling market," said chief executive Francis Salway.

Land Securities said it had achieved its best performance relative to Investment Property Databank yardsticks, trumping the IPD All Property index on investment properties by 6.5 per cent.

But this performance was offset by hefty falls in pretax profits and adjusted diluted net asset value, both badly bruised by the markdown in the value of its portfolio.

The company posted a 10.3 per cent fall in adjusted diluted net asset value to 1,956 pence and a £888.8 million pretax loss, compared with a £1,979 billion pretax gain the previous year.

It boasted a 16.4 per cent hike in adjusted diluted earnings per share to 81.71 pence, largely driven by lower taxes in its first full-year as a tax-efficient real estate investment trust.

While it did not provide further details on the timing of its planned three-way split into a distinct London property company, a retail real estate specialist and an outsourcing firm, Land Securities said it was progressing plans "with a steady hand", and ratings agencies had provisionally indicated AA ratings. for the London and Retail company debt programmes.