Kitcatt Nohr Digitas

Just round the corner from the hustle and bustle of St Paul's Cathedral is one of the most touching places in the City of London. Postman's Park, a tiny green space tucked under the shoulder of the General Post Office, is a space where concentrated emotion dwells quietly.

It is home to fifty simple plaques that pay tribute to the heroism of ordinary folk who gave their lives trying to save other people.

And in less space than a modern-day Tweet, they manage to tell entire stories of pathos and self-sacrifice.

The plaques were the brainchild of painter GF Watts, who proposed in 1887 that ordinary heroes should be honoured in this way as part of the celebrations for Queen Victoria's Golden Jubilee. Perhaps predictably, his proposals fell upon stony ground, and it fell to Watts himself to find a way to commemorate them with a small pavilion in this still, small space next to a City church, started in 1899.

Watts devised a plan to create plaques made of hand-painted Royal Doulton tiles, designed in an understated, art nouveau fashion. Each of them tells a heartbreaking story (in fewer than 140 characters).

Some will simply make you cry, such as 'David Selves, aged 12, of Woolwich who supported his drowning playfellow and sank with him clasped in his arms'.

Others are tragic and comic at the same time, like the pantomime performer Sarah Smith, who 'died of terrible injuries received when attempting her inflammable dress to extinguish the flames which had enveloped her companion.'

Collectively, their effect is overwhelming. And more than a century later, these concentrated bursts of emotion are still as powerful as the day they were painted.

Do any of us believe that any Tweet will have that power in 100 days' time, let alone 100 years?