Wealthy Londoners race underground before basement bonanza ends LONDON (Reuters) - Wealthy homeowners in some of London's most affluent neighborhoods are racing to build luxury basements with swimming pools and wine cellars before new rules limiting underground developments come into force. Over the past decade a growing number of property owners unable to build up or out in tight London streets have opted to dig down, bypassing rules governing above-ground work and encouraged by technological advances in building basements. Tetra Pak heir Hans Rausing this week joined the list of the super wealthy to get approval to build a pool, cinema, and cigar room under his London mansion where his wife's body lay hidden for two months last year after her drug-related death. Chelsea Football Club owner Roman Abramovich, Formula 1 heiress Tamara Ecclestone, and steel tycoon Lakshmi Mittal are among those dabbling with basement extensions in recent years. But the construction of mega basements is about to be reined in with authorities in the two most affected London areas finalizing stricter rules for subterranean work in response to community anger about the disruption and structural impact. Final comments on the plans had to be submitted this week. Resident groups around London have grown increasingly angry about basement extensions causing noise and disturbance during construction, traffic problems, vermin, and fear developments will impact structural stability of nearby buildings. "There were just no rules and we've had quite a few accidents, such as a skip (dumpster) cracking through the street and water leaking into neighboring properties," said Randa Hanna, spokeswoman for the Belgravia Residents' Association. There really has been an astronomical rise in the number of basement developments, many of which were not monitored properly, and introducing some rules is a step forward. Kensington & Chelsea and Westminster councils' plans to introduce new rules in early 2014 to target and restrict basement development prompted a rush of applications this year. The new rules will make major basement extensions more difficult as excavations deeper than one storey will only be allowed in exceptional circumstances and basement extensions covering more than 50 percent of the garden will not be allowed. Developers expect other councils in London may follow suit. "This summer we've seen people rushing to get consent for basement developments, advised to do so by us and their architects," said Charlie Bubear, head of the Chelsea office of Savills real estate agency. This can add significant value to a property. Basement conversions are the only way to go if you want to extend and it avoids the costs of having to move but you can understand resentment to living next to a building site. Bubear said it costs about 500 pounds ($780) per square foot to build a basement but properties in the area sell for up to 2,500 per square foot with double digit price rises annually. A spokeswoman for Kensington & Chelsea Council, one of Britain's most expensive areas where semi-detached houses cost an average 6.1 million pounds ($9.5 million), said a record number of applications had been received this year. In the first five months the council received 166 basement applications compared with 297 in all of 2012 - a sharp contrast from 2001 when 46 basement applications were submitted. Since 2009 it has received over 1,000 applications and approved nearly 800. Hanna said the new rules should slow down the pace of basement developments but they would not stop it altogether. "It is too much to say you can't build in your own home but these developments need to be monitored better," she said.