A woman who tied her three-year-old son to his pushchair and abandoned him for 10 days while she visited her new boyfriend was yesterday beginning a 15 month jail sentence.

The woman, who cannot be named to protect the identity of her son, made daily visits to check on the boy and feed him, Merthyr Tydfil crown court heard. But when police found him, he was dressed in a urine-soaked sweater and was shaking uncontrollably. Both his feet were red and swollen and he was unable to straighten his legs.

Doctors who examined him found he was under-nourished, dehydrated and suffering from skin conditions and from emotional and physical neglect. He weighed only 2lbs more than he had when aged 20 months.

Sue Ferrier, prosecuting, told the court that the woman, from Merthyr Tydfil, south Wales, had convinced friends and neighbours the boy was being looked after by his grandmother while she stayed with her boyfriend and paid visits to a sick friend.

Police were eventually alerted by the boy's grandmother who had not seen him for three months. They broke into the house, described in court as squalid and strewn with litter, and found the boy strapped into his chair so tightly he needed to be cut free.

In police interviews the woman, who admitted neglect and wilful abandonment, told police she "could not cope" and did not have enough money to look after her son.

Jeremy Jenkins, defending, said: "She could not hide from the fact that her son was in a deplorable state. It is clear from the evidence that the mother needs help."

Judge John Curran rejected pleas for the woman to be placed on probation or given a suspended sentence. "The offences are too serious to be dealt with by anything short of a custodial sentence," he said.