EastEnders fans spot blunder as the back of the set is visible as Sonia Fowler answers the door

EASTENDERS fans spotted a jaw-dropping blunder - when Sonia Fowler walked past the bare back of the set as she went to answer the door.

Just to the right of actress Natalie Cassidy was the false wooden wall with a warning to the BBC soap's crew pinned to it.

Although only glimpsed for seconds, the flimsy-looking structure was unlike anything you'd normally see in an Albert Square living room.

On it was a notice to the soap's technical crew insisting: "DO NOT SET AND STRIKE" with another smaller warning underneath.

The piece of set was exposed when Sonia walked out of the lounge, where Dot Cotton had been complaining about the night's TV.

It formed part of the action on Friday's night's episode - but whizzed past so fast that many viewers missed it.

As the doorbell rang, Walford icon Dot asked tersely: "Oh, who's that?"

Sonia offered: "Shall I get it?" before striding out to the hallway - past the glaring piece of wooden set.

However, the bare wall wasn't visible when Sonia returned with two police officers, as the camera was trained in close enough to keep it out of shot.

"Can we have a word?" they asked Martin before quizzing him over a string of car thefts.

He denied ever leaving the house except to get some chocolate, leaving the sceptical cop asking: "Can anyone vouch for that?"

Sonia suddenly appeared, saying: "I can. He went out just for those few minutes. Can't get rid of him."

However, once the officers had gone, she asked: "Did I just give you a false alibi?"

It quickly emerged that she had - as well as giving viewers a glimpse of false wall.