Senior lawyer Lee Suet Fern has been suspended for 15 months by a Court of Three Judges over her handling of the last will of her late father-in-law Lee Kuan Yew.

The highest disciplinary body for the legal profession found her guilty of misconduct unbefitting an advocate and solicitor.

She had "blindly followed the directions of her husband, a significant beneficiary under the very will whose execution she helped to rush through", it said in a written judgment released yesterday.

This followed a hearing in August, after the Law Society applied to have Mrs Lee struck off the roll.

A disciplinary tribunal (DT) had earlier this year found that she and her husband had misled the senior Mr Lee to sign a new will without the advice of his usual lawyer, Ms Kwa Kim Li.

While the court found Mrs Lee and the senior Mr Lee were not in a lawyer-client relationship - which would have made her conduct more grave - it agreed with the DT that she was guilty of misconduct.

The case centred on the role she played in the preparation and execution of Mr Lee's last will, which was signed on Dec 17, 2013.

His last will differed from his sixth and penultimate will in significant ways, including the distribution of his estate among his three children as well as the demolition of his house at 38 Oxley Road.

It also did not contain some changes he had wanted and discussed with Ms Kwa four days earlier.

The DT had found Mrs Lee guilty of grossly improper professional conduct in February this year.

The Law Society subsequently applied to have her struck off the roll, and the case was referred to a Court of Three Judges.

The court held a virtual hearing in August, where the Law Society set out its arguments for why she should be disbarred, while Mrs Lee's lawyers called for all charges to be dropped.

In its 98-page judgment, the court, comprising Chief Justice Sundaresh Menon, Judge of Appeal Judith Prakash and Justice Woo Bih Li, said Mrs Lee had acted at the behest of her husband to push through the execution of the will in an "unseemly rush".

The will was signed 16 hours after she sent a draft of it to Mr Lee.

The court noted that she had forwarded the draft, which was to have been based on the first will, without verifying if it was the correct version.

This showed a "notable lack of diligence" on her part, it added.

She was also content to have Mr Lee sign the last will on the basis of her "unconfirmed and ultimately untrue representation".

She did it even though she knew she had no way of verifying the draft since she did not have the signed version of the first will.

As such, it was "clearly imprudent and grossly negligent" for her to have held out the representations she made about the draft last will as true.

The court further said when Ms Kwa - who had drafted and executed the senior Mr Lee's first to sixth wills - was left out of the e-mails by Mrs Lee's husband, Mr Lee Hsien Yang, Mrs Lee acquiesced to it and did not seem to pause to reconsider her position.

On the contrary, she had gone ahead to act on her husband's wish to have the last will executed with "seeming haste" by arranging for her colleagues Bernard Lui and Elizabeth Kong to witness the signing.

She did it even before the senior Mr Lee had responded to his son Lee Hsien Yang's suggestion to proceed.

This action effectively assured her father-in-law the required checks had been done to make sure the draft last will reflected his wishes, the court said. It also noted she had conceded her father-in-law would have believed and relied on her representations.

Describing Mrs Lee's conduct as "especially unsatisfactory", the court added that there was a "remarkable lack of diligence" on her part in ensuring her father-in-law's wishes were properly ascertained and carried out.

The court noted, among other things, that she subsequently did not update Ms Kwa fully and frankly about what had transpired, and merely wrote her an innocuous quick note which said the will had been signed.

Whether intentionally or not, it left Ms Kwa with the impression there was nothing left for her to do, and removed any signs for any cause for concern on her part, it said.

It also said Mrs Lee might have mitigated her culpability if she had briefed Ms Kwa fully on the circumstances surrounding the signing of the will.

This might have conveyed some of the sudden urgency with which matters had proceeded and prompted further inquiry from Ms Kwa. "However, none of this was done," it added.

Given her 37 years of experience, it noted "she could not have failed to know that the veracity of her representations was something that absolutely needed to be checked".

The court added: "It is simply untenable that the need for caution, restraint and circumspection did not strike (Mrs Lee)."

In underlining the importance of dealing with wills, the court rejected the argument made by Mrs Lee's lawyer, Professor Walter Woon, that it was sufficient the draft sent to her father-in-law was broadly similar to the version he had wanted.

This, the court said, suggests it is unimportant to ensure wills accurately reflect a testator's intentions.

"A solicitor who fails to act with exceptional care and, where appropriate, as it is here, with restraint and circumspection must be prepared to have her conduct scrutinised and, perhaps, even her motives called into question," it added.