ON Thursday night last week I was in London having dinner alone in a Middle Eastern restaurant. As usual my companion was my newspaper.

I took a seat by a window so I could people gaze and avoid the stares of couples and groups at other tables looking at me as if I was Billy No Mates.

Looking out, I occasionally glimpsed a woman at a window several floors up in a Georgian terrace along a side street.

Returning to my paper, a few seconds later there was a commotion outside which caught the attention of the other diners.

I looked across the road to see scores of people running to the pavement below the house where I had noticed the woman.

The chef left the kitchen and the waiters went outside to watch the unfolding drama. Ambulances and police were quickly on the scene and the woman’s body was taken away with some onlookers actually videoing the emergency services and the unfortunate lady.

My waiter causally, and without any trace of sympathy, remarked to us diners: “Some people are lucky – they do something like that and they survive.”

Unsurprisingly, I lost my appetite.

The event reminded me of another tragedy I witnessed a long time ago in Kew.

After waiting months to get a reservation in a celebrity-owned restaurant, I was walking across the green towards the renowned eatery when a lady walked out in front of a bus.

The poor woman looked as if she lived on the streets and probably, like many street people, suffered from mental health issues.

The bus dragged her under and the car behind hit her too.

I ran over, took off my rain coat and put it over her as we waited for the emergency services. I felt so useless.

I have no practical training or instincts for such situations. I am a tad superstitiously religious and always carried a Rosary ring and a miraculous medal.

I still do today. There, on the spot, I prayed for this lady and took the medal from my wallet and slipped it into her pocket.

On reflection the prayers did more for me than her. When the emergency services arrived I walked to the restaurant but like last Thursday I had no appetite.

A policeman came in to the restaurant and returned my rain-soaked mac, now stained with blood and London grime. I had no inclination to dry clean it so I dumped it in a bin on the way back to my house.

Churchill called it his ‘Black Dog’ but most of us know it as depression and it probably affects us all at one time or another.

It is sometimes just a fleeting moment when everything around looks bleak. Often it requires no help, just a belief in the fact that the sun always rises on a new day.

A very successful Irish businessman once told me that there was a time in the 1970s when, with a large family to support, he was struggling on his uppers to try and find a means to survive.

He got a lucky break and his fortunes changed. But he never forgot the darkness of those torturous days nor the sleepless nights. It’s something that has probably driven his sense of philanthropy ever since.

The recession was tough for many people but particularly for small business owners. It lasted so long that some couldn’t take the burden.

Many of us who ran businesses throughout it know all about the fatigue of mental stress and the weariness that creates a restlessness which in turn refuses to let the brain relax for sleep.

Many cannot share those feelings with loved ones because they are trying to protect them too. All of which increases the burden and invites the Black Dog in.

Teenagers and children are not immune to such feelings either. Cyber-bullying has left many feeling isolated and victimised.

The internet means there is nowhere safe for them as it can reach right into the private sanctum of their bedroom – once a refuge for truculent teenagers.

A friend with two children confided in me that she was at her wits’ end with her son’s behaviour whilst he was being bullied online.

Things came to a head when her nine-year-old lad tried to throw himself from the car whilst she was driving.

We may fear conditions like cancer, dementia or heart failure but we need to be more aware of the stealth murderer that is depression because where the Black Dog stalks, not everyone survives.