New figures obtained by The Lawyer show that estate agency Hambro Countrywide is now the largest conveyancer in England and Wales.
Hambro Countrywide Conveyancing (HCC) dealt with 15,000 instructions from clients from January to September this year and aims to be dealing with around 30,000 in 1999.
"I would be extremely surprised if any other firm in the country was doing that volume," said HCC operations director Roger Wilson.
HCC has kept its operation under wraps since it was established in 1997, partly because of teething problems co-ordinating its service with its law firm partners.
But HCC managing director Bob Scarf now claims the operation's success in the last nine months will lead to a "shake-up" in the high street with many firms unable to match Hambro's investment in technology.
Hambro said setting up the operation was made easier due to a lack of "co-ordinated" opposition from the legal profession.
Hambro linked up with law firms Shoosmiths & Harrison, EDC Lord & Co and Eversheds, to offer house buyers a "fast track" high-volume conveyancing service in March 1997.
Its in-house conveyancers work for the client on one side of the deal, while volume conveyancers at the three law firms work for the purchaser or vendor on the other.
But Hambro also works with high street firms where the client on the other side of the deal insists on it.
Hambro estate agency customers simply phone one of HCC's conveyancing centres with no need to visit their solicitor to get the deal done. The service costs £350, with no charge if the deal falls through. Hambro says around 15 per cent of their deals fail to complete.
Three HCC centres were originally set up in 1997 but there are now five located in Manchester, Cardiff, Brentwood, Northampton and Woking. The number of staff in the Woking office alone has grown from 17 to 280 since HCC started.
However, Hambro said it is not yet looking for any more law firms to join the scheme and it flatly denied market rumours that EDC Lord was to be dropped.
Sole Practitioners' Group press officer Montagu Martin said the figures were not yet reflected in a drop-off in work for SPG members but were a "concern". High street practices had to co-operate more to ward off the Hambro threat, he said.
Law Society spokesman David McNeil said: "Many people will choose to pay more for the personal service they can get from people they have worked with before on the high street rather than with a conveyancing factory."
Hambro has so far spent around £1.7m on establishing its conveyancing service, with the first profits expected next year.