An Italian herringbone raglan coat, cotton twill overshirt, 
straight fit essential chino and Converse high tops, all from John Lewis in Britain.

LONDON — British department store John Lewis & Partners, where customers can find everything from lamps and frying pans to flat-screen TVs and computers, is putting a fresh spin on men’s wear in a bid to speak to multiple generations, street and sneaker devotees and necktie-free urbanites.

The retail stalwart, which also owns the upmarket supermarket chain Waitrose, has held relatively steady in the crisis that is sweeping the British high street. The store continues to invest in its store real estate, own-brand merchandise, staff training and has been swinging the spotlight onto own brand and exclusive products that customers cannot buy anywhere else.

It’s a tough time for British brick-and-mortar clothing retailers in particular. They’re falling victim to online competition, fast-fashion and streetwear competitors, as well as luxury brands keen to woo younger shoppers with entry-price merchandise such as sneakers and T-shirts.

Marks & Spencer is a prime example of the struggle so many are facing: On Thursday the retailer said in a terse statement that its managing director of clothing and home, Jill McDonald, was leaving the business after two years.

M&S clothing has been struggling for some time, a victim of long-standing supply chain and sizing issues and of a younger generation that automatically looks to competitors for seasonal fashion and basics. The store’s chief executive officer Steve Rowe will take over the business directly in the near-term, as the company looks to shrink its clothing offer and put a bigger focus on style and fashion.

By contrast, John Lewis relaunched its women’s wear last year and watched sales in the division climb 12.9 percent in the six months to March 31. This year the retailer is going for an encore performance, making its most significant men’s wear investment to date, with a mix of in-house and branded clothing and accessories that have a younger, more urban attitude.

Come September, the store will be offering a broad collection featuring pieces such as peacoats, puffers, denim and cotton trousers and shirts, cashmere knits, sneakers, and stretchy, machine-washable suits, all in a mix of technical and natural fabrics.

Men’s wear will be anchored by two stand-alone in-house brands: John Lewis & Partners, a 280-piece collection that takes a fresh view on classic pieces, and Kin, a contemporary in-house brand that launched in 2013.

The retailer plans to weave in emerging brands and keep its established ones, such as Gant, Barbour, Ted Baker, Ralph Lauren and Tommy Hilfiger.

Since January of this year, the retailer has introduced 17 brands into the men’s space, including Wax London and Les Basics. Most are producing exclusive designs for the store.

Those additions have already fueled a 3 percent increase in sales and a 15 percent rise in new customers shopping at John Lewis. In the autumn, the store plans to add laid-back contemporary labels Folk and Albam to the mix. The store will carry collections called It’s All Good Folk and Albam Utility.

Prices range from about 20 pounds for hats and accessories to 650 pounds for a shearling coat. Basic cashmere sweaters will retail for about 80 pounds.

The new men’s wear proposition will come with a new shopfit and personal styling services, which are both set to be unveiled this fall. Changes will begin with the John Lewis Oxford Street flagship, which will see men’s wear expanded to 20,000 square feet.

Some 20 percent of the floor space will be dedicated services and 1,000 square feet will be transformed into an experiential space aimed at getting customers to try something new. John Lewis also plans to bring in events such as themed styling talks and to cross-sell tech brands and other relevant merchandise in the men’s wear space.

As with women’s, the new shopfit and services will roll out to all John Lewis & Partners stores, of which there are 50 across the U.K.

The aim is to have men’s wear sales split evenly between in-house brands and outside brands, and to double John Lewis’ men’s wear market share, which is less than 5 percent, over the next five years.

Simon Coble, trading director of John Lewis, whose résumé includes Uniqlo and The Body Shop, said the success in women’s over the past months has laid the groundwork for the risks the retailer is prepared to take in men’s wear.

“It’s an evolution for us,” he said during a walk-through of the new collections. “The customer has seen what we we’ve done in women’s wear, so the men’s wear conversation is easier to have.”

Beth Pettet, head of men’s wear at John Lewis & Partners, said the store has put the customer at the heart of the new men’s plan and is “striving to offer an independent point of view with our dynamic design and buying approach.” She said the aim is to offer a shopping experience “that customers cannot find anywhere else.”