Eric, the nicest dog I've ever met

He was standing patiently on the lawn wearing gumboots and being used as a bouncy castle

It was what the gossip columns would have described as a glittering evening in London's West End. Everyone who is anyone was there – Cilla Black, Stephen Fry, Joanna Trollope, Ned Sherrin, the Prince of Wales – well, it was his house. "Let me give you some more champagne and introduce you to the Home Secretary," someone said, and I promptly fell over Mr Blunkett's guide dog, Lucy, who was lying across the entrance to the ballroom of St James's Palace looking bored. I can't say I blamed her. There are limits to how long you can talk about The Archers and since this was a party for Archers enthusiasts to celebrate 50 years of the radio soap, Lucy had clearly run out of steam.

News of her retirement prompts me to wonder whether Mr Blunkett wouldn't be better off with a male dog, blokes on the whole being better suited to the time-honoured role of best friend, loyal retainer and political animal than temperamental bitches. Now if Mr Blunkett's Lucy had been anything like as caring or as attentive as my sister's guide dog Lennie, she wouldn't have been sprawled indolently over the carpet. She would have been sitting alert, ears pricked at the Secretary of State's feet, making sure his glass was full and the waitress was heading his way.

It must be 15 years since my sister Jennifer went off to train and be trained with her first guide dog. This may be the moment to give you some facts. In Britain there are about 5,000 working guide dogs, which cost the Guide Dog Association £35,000 in food, vets' bills and sundries to maintain throughout their working lives. All puppies from one guide dog litter are given names beginning with the same letter, like car registration. This was an E-reg litter and out of the seven pups, Ella, Evie, Emily, Eddie, Elvis and Everton. My sister had Eric who was without doubt the nicest dog I've ever met. This is praise indeed. Give or take the odd border collie I occasionally run into in the West Highlands rounding up sheep, I am not a dog lover.

Eric was different. He had a soul. It was not just the way he looked after my sister, sizing up the best route to take her down a busy street, side-stepping to avoid some overhead obstruction which wouldn't affect him but might hit her. It was the soulful expression in his eyes. Jennie had three small children when Eric arrived, so as well as being streetwise he had to be toddler-friendly. The first time I saw Eric he was standing patiently on the lawn wearing two pairs of gumboots, being used alternatively as a climbing frame and a bouncy castle.

The English, everyone knows, love dogs. Their attitude to guide dogs is something else. On one occasion when Jennie and Eric were walking on an uneven pavement beside a country road, she tripped and fell over, taking Eric with her. Immediately there was a screech of brakes, a car pulled over, the driver leapt out, raced over to where my sister was lying and said: "Is the dog all right?"

I gather Lucy is going to retire to Bolton with an ex-boyfriend, Barney, now that her younger sister Sadie has taken over the mantle of guiding the Home Secretary. I wish her well. When Eric retired and L-reg Lennie was put into harness, Eric stayed on as a sleeping partner.

The working life of a guide dog is about seven years, but Eric hung on in there for much longer. Towards the end of his career, I remember, he and my sister used to come up to London every day to take part in an exhibition sponsored by BT on the South Bank called Dialogue in the Dark. Blind guides, my sister included, took sighted visitors through various stage sets to demonstrate what it is like to be visually impaired. Sometimes the visitors reacted badly to their pitch-black surroundings and screamed to be let out. One man, Jennie told me, suddenly stopped on an ornamental bridge in the middle of the garden set, took off all his clothes and started yelling: "I'm free, I'm free."

After work one day, she and Eric came round to the flat. It's four floors up with no lift, and when they got to the top Eric was panting furiously. "Does he want some water?" I said. "I'm sure he does," said my sister, but Eric didn't seem to be interested. "You'll have to put his nose right into the bowl," advised my sister, "because his eyes aren't very good."