Now that the House of Lords has removed advocates' immunity in the case of Hall v Simons, few practitioners are going to worry about why it existed until July 2000. What they will want to know is where they go from here.

It is clear that actions will be brought against barristers alleging in-court negligence and that some will succeed. But their Lordships were at pains to stress that they did not believe they were opening the floodgates. There are at least three significant obstacles for claimants to overcome in this type of case.

First, proving negligence will be difficult. Advocacy is an art not a science and, as Sir Thomas Bingham said in the context of wasted costs in Ridehalgh v Horsefield, a judge "must make full allowance for the fact that an advocate in court, like a commander in battle, often has to make decisions quickly and under pressure, in the fog of war and ignorant of developments on the other side of the hill."

Second, CPR part 24.2 provides that the court may give summary judgment in favour of a defendant if it considers that the "claimant has no real prospect of succeeding on the claim". This is a much lower hurdle than the old "frivolous and vexatious" test.

Third, the rule against the abusive collateral attack means that a defendant who has been convicted after a criminal trial will usually not be able to bring a negligence claim against their lawyer until their conviction has been quashed. The spectre of clients hunched over a 15-year-old copy of Archbold plotting revenge on their barristers appears to have weighed on their Lordships' minds.

Advocates in Canada have never had immunity, but there have been very few cases arising from in-court negligence. We must wait to see whether the UK experience is the same.

Mark Simpson is a barrister at 4 Paper Buildings. He represented the Bar Council in Hall v Simons.