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M&S

Heatgen™ Maximum Thermal Long Johns

£28

Colour

Size

Also available in: Long Sleeve Top and Vest
Free standard delivery over £60

Product code: T147412W

About this style

These thermal long johns combine warmth with comfort through our warming Heatgen™ fabric. Cut to a regular fit with an elasticated waist and cuffed bottoms for secure, comfortable wear. The base layer underwear keeps you warm throughout the day, while the brushback texture feels gentle on skin. Supersoft seams prevent chafing, and a keyhole fly adds everyday practicality. Perfect cold weather clothing for when temperatures drop. M&S Collection: Easy-to-wear wardrobe staples that combine classic and contemporary styles.

Maximum warmth for keeping cosy in colder climates.

Details & care

Style

Regular fit

Features

Thermal

Soft and cosy brushed fabric that keeps warmth in

Heatgen™ technology

lightweight and supersoft, designed to keep you warm when the weather gets chilly

Composition

35% wool, 26% polyester, 23% viscose and 16% polyamide (exclusive of trimmings)

Care

Wash at 40°C

Do not bleach

Tumble dry medium temperature

Iron at low temperature

Do not dry clean

Delivery, collection & returns

Delivery

Standard

UK Standard Delivery is available for £3.99 or free on orders over £60 (excluding furniture).

Nominated Day

UK Next Day Delivery and UK Nominated Day Delivery (excluding Northern Ireland) are available for £5.99 (excluding furniture)

Collection

Collect from store

Store collection is free on all fashion, home and beauty orders.

Returns

UK returns

Free

Exclusions apply

Full delivery and collection informationOur returns policy

Reviews (663)

4.7

74% Recommended this product

Mentions
03 February 2026ChrisPacket
Verified Purchase

Warm!

Bought for travelling in a northern Norway winter. Have worn them under jeans and have kept me warm for the couple of hours each day when Im out walking.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

01 February 2026Neera
Verified Purchase

Warm and cosy

Yes, I recommend this

Warm and cosy. Great to wear in the winter periods

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

01 February 2026RSP
Verified Purchase

First class. Very warm and cosy.

Yes, I recommend this

First class. Great quality would definitely buy again

Helpful?

31 January 2026Smart Mart
Verified Purchase

Long John Silver

Yes, I recommend this

These are brilliant! I was looking for something to complement a lighter pair of trousers that I want to wear in cooler conditions and these are it! I've even worn them with winter cords to boost the warmth factor. They're close-fitting, comfortable and a superb purchase.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

28 January 2026Rob 1690
Verified Purchase

Good quality and reasonably priced

Yes, I recommend this

Very useful and beneficial at this time of year. Good quality and reasonably priced

Reviewer Ratings

Comfort

Good

Helpful?

Reviewer Ratings

Comfort

Good

27 January 2026ClaireMiao
Verified Purchase

Warm and comfy

Yes, I recommend this

Got these for my husband, he loves them, says they are very warm, no more cold legs.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

25 January 2026K N Medora
Verified Purchase

Great quality

Yes, I recommend this

Perfect for me as I work in a very cold environment

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

25 January 2026TheBestInTheWest
Verified Purchase

Great when the heating broke down.

Yes, I recommend this

Hubby approves. Garment with flies is convenient. Kept him warm when our heating broke down.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

24 January 2026Gonkie
Verified Purchase

Great quality

Lovely soft thermal leggings. My dad loves to wear these for extra warmth

Helpful?

23 January 2026Swimmer1960
Verified Purchase

Great quality

Yes, I recommend this

Brought for husband already has some just buying more

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

18 January 2026Ricardian
Verified Purchase

Excellent!

Yes, I recommend this

Well made and very comfortable. Would definitely buy again.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

18 January 2026Tadpole40
Verified Purchase

Very comfortable to wear

Yes, I recommend this

Great quality thermals that are warm, fantastic for the chilly Winter months. I could recommend this product if you feel the cold. They wash well, I have bought them in the past and would buy again.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

17 January 2026Rosie2step
Verified Purchase

Disappointed

No, I don't recommend this

Bought to give added warmth for my 91 year old husband but he says they’re no warmer than the ones he already has which aren’t thermal

Helpful?

15 January 2026C4D4149
Verified Purchase

Good &Bad

No, I don't recommend this

They were supposed to be size 38waist 31leg but they were much too tight I couldn’t even do them up the other trousers were a perfect fit

Helpful?

15 January 2026Bazz63
Verified Purchase

Highly recommend for all ages!

Yes, I recommend this

Bought for my son, who works outside throughout the night. With the recent dip in temperatures he was really suffering with the cold. They have made a huge difference to how he feels and he is planning on buying more. . Very comfortable and keep him warm.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

14 January 2026Maff1
Verified Purchase

Warm and comfy

Bought for my husband, he loves them. They are quite thick, but not too thick to fit perfectly under clothes. Definitely would buy again.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

14 January 2026old man in a warm shirt
Verified Purchase

Amazing !

Yes, I recommend this

Excellent for the cold weather but it has to be cold to be comfortable

Reviewer Ratings

Comfort

Good

Helpful?

Reviewer Ratings

Comfort

Good

13 January 2026Natasha 25
Verified Purchase

Helps to keep the heating off!

Yes, I recommend this

Significantly warmer than the medium version so battles with my husband about the heating are less when he wears these ones! Soft and comfortable for him too.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

12 January 2026GARNO
Verified Purchase

Comfortable

Comfortable and warm. Good size and fits well under trousers.

Helpful?

12 January 2026Choosie buyer
Verified Purchase

Keep warm

Yes, I recommend this

Very light to wear plus very warm and cosy to wear.

Reviewer Ratings

Comfort

Excellent

Helpful?

Reviewer Ratings

Comfort

Excellent

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