It's normal to wear a stab-proof vest to tour my constituency

Labour's deputy leader and Leader of the House was mocked for her decision to dress up in the Kevlar-reinforced jacket to walk the streets of Peckham with four police officers.

It seemed a classic case of a political photo-opportunity backfiring - with Ms Harman accused of looking afraid to go out without protection after rises in violent crime.

One Peckham resident criticised the politician for wearing the vest. Beatrice Smith, 63, said: "The only time we see Harriet Harman is either on voting day or doing some PR stunt. There is a lot of trouble on the estates but we don't get given stab vests."

This morning Ms Harman dug herself deeper into the mire by revealing that she constantly dresses up for different situations. She said: "I was not parading the streets of London in a bulletproof vest - I was going out with my neighbourhood police team.

"Just as I might wear a hard hat on a building site or an Indian outfit going to meet Indian constituents, it's just about wearing the kit."

Ms Harman published a photograph of her in the vest with four similarly dressed police officers to publicise the Government's new neighbourhood policing.

But she seemed to have forgotten the recent row in which Home Secretary Jacqui Smith admitted being scared to walk the streets alone at night. Aides of Ms Smith compounded her error by saying she had bought a kebab in Peckham, only for it to emerge that she had been accompanied by a Special Branch protection officer to purchase the takeaway.

Both incidents gave the impression that ministers are afraid to go out at a time when Labour is making cutting crime a centrepiece of its local election campaigns.

Ms Harman told BBC radio the allegation was "ridiculous" and " malicious". She went on: "I don't have to wear a stab-proof jacket. I had it on just as a courtesy to the team. It's like when you visit a meat factory, they give you a white hair net but they don't expect you to make a meat pie. There was no security issue whatever. The idea that I put that on because I was fearful of being out and about in my own constituency at nine in the morning is just ridiculous."

However, local police were reported to have been "flabbergasted" that she accepted an invitation to wear the protective-vest. One said: "Senior politicianswho have visited Peckham in the past have never worn one."

The danger to Ms Harman now is that she will appear insincere by admitting that she changes outfits to suit different audiences and occasions.