People sign their names again and again during their lifetime, and signatures are often very recognisable. A signature is sufficient to bind people into all sorts of obligations - from something as small as a cheque for a child's dinner money to something as big as buying a house.
A will must be signed in order to be valid (s9, Wills Act 1837). Previously the Court has accepted variations on what might traditionally be thought to be a signature - for example the words 'your loving mother', an inky thumbprint or the testator's initials. In this day and age, where there are high levels of literacy and pens and paper are in ready supply, it is unlikely that the Court will accept much less than a 'proper' signature. This can be difficult to obtain where the testator is very frail and unable to hold a pen. In those circumstances, another person can sign on behalf of the testator so long as the testator is present (both physically and mentally) and it is done at his direction.
The long running case of Barrett v Bem  EWCA Civ 52 concerned the question of whether Mr Lavin had signed his final will. He made a will on the day of his death. He was a bachelor with seven siblings whose final will left everything to his eldest sister Anne. This upset other members of the family who had been due to benefit under an earlier will.
The disputed will was handwritten by a niece on Mr Lavin's directions. She had previously been a legal secretary. She explained the will to Mr Lavin and gave it to him to sign. Two nurses were witnesses. Both the niece and one of the nurses gave evidence that they saw Mr Lavin sign unaided. The other nurse could not be traced. The judge concluded (on the basis of expert handwriting evidence) that Mr Lavin could not have signed the will himself unaided. The will was held to be invalid.
Following judgment, the second nurse witness was traced, and said that she was certain that the pen had been in Mr Lavin's hand when he had signed the will. The Court of Appeal allowed a retrial on the basis of fresh evidence.
By the time of the retrial, the niece had changed her evidence to say that she remembered her mother (Anne - the sole beneficiary of the will) holding Mr Lavin's hand or wrist to stop it shaking and to enable him to sign. The first nurse witness also changed her evidence to say that Anne had held Mr Lavin's hand - but not the pen. The signature was said to be a 'guided hand' signature. However, the judge rejected this evidence and said that Anne had signed the will at Mr Lavin's direction and the will was valid.
That decision was appealed, and overturned on appeal. The Court of Appeal held that a will should not be found to be valid in these circumstances unless there was positive and discernible communication by the testator that he wanted someone else to sign on his behalf. The attestation clause should reflect that. There was insufficient evidence that Mr Lavin had directed Anne to sign on his behalf, and his final will was again declared invalid.
Those making wills at the very end of life or when frail should be very careful to ensure that their signature is properly recorded and unlikely to be challenged. The attestation clause should be clear and appropriate. If a solicitor is advising, then a clear attendance note will help.
In this case, the court proceedings spanned 8 years, involved 4 hearings and no doubt used up a vast amount in legal fees. By the time that the matter was decided, Anne was dead, as were many of her siblings. It is worth ensuring that the formalities for wills are strictly observed in order to avoid the costs and stress of a court battle of this sort - especially when you may not live long enough to see the outcome.