The Post Office takes a pop at Facebook during blackout

The Post Office is poking fun at the online communication platforms that went down for 6-hours on Monday.

The outage, which caused a stir across the globe and affected Facebook, Instagram and WhatsAapp, reportedly led to billions of dollars being wiped off of owner Mark Zuckerberg's portfolio.

The poster campaign is now showing on Clear Channel sites across London and is soon to be shown nationwide.

Speaking yesterday, Jules Chalkley, executive creative director at Ogilvy UK, said: "We wanted to take advantage of last night’s [Monday's] social media outage to celebrate the Post Office. Whilst the world went into digital turmoil, Post Office did what it has always done: be the original social media network, connecting people day in day out, all over the country in a beautifully human way."