With the ISA deadline fast approaching, I’ve been scouring the London stock market for last minute additions. Today I’ve been digging through the FTSE 250 for the best undervalued UK growth shares to consider buying.

My research has unearthed the following bargain-basement growth heroes:

As you can see, both of these FTSE 250 stocks are tipped to deliver double-digit earnings growth in the current financial year.

They also trade on a rock-bottom price-to-earnings growth (PEG) multiple below the value marker of one.

Here’s why I think they’re worth serious consideration from shrewd ISA investors.

Chemring

Chemring — which manufactures countermeasures and sensors for the defence industry — is thriving as arms spending accelerates in the West.

Its latest contract win last month was £26m, a multi-year agreement with “a major US prime contractor” to supply radar technology.

It follows news that revenues rose 8% in Chemring’s last financial year (to October 2024). Its order book also leapt to record highs of £1.04bn in the last fiscal period.

WIth geopolitical tensions rising and NATO budgets increasing, the FTSE 250 firm looks in good shape to win lots more business in the future. This should be supported by capacity increases for its countermeasures operations in the US and UK, and potential expansion in Norway (which it is currently exploring).

I’m also excited by Chemring’s improving presence in rapidly growing areas of artificial intelligence (AI), cyber warfare, and electronic security. These phenomena drove sales at its Roke unit 13% higher in financial 2024.

Supply chain issues in the defence industry remain a threat. And on the sales side, demand from the US could be adversely affected by spending reviews from Elon Musk’s Department of Government Efficiency (DOGE).

Yet on balance, I think Chemring’s a top stock for growth investors to consider. And particularly at today’s price.

Spire Healthcare

With its large footprint of 39 hospitals and 50 clinics (and other facilities), Spire is one of the UK’s largest private medical services providers. As a result, sales and profits are soaring as severe pressure on the National Health Service (NHS) drags on.

The reasons for this trading boom are twofold. NHS-related business is growing as the government pays private healthcare providers to clear patient backlogs. Revenues from this source rose 5.2% in the six months to June.

Trade is also booming as people sidestep long NHS waiting lists and fund their own treatments. Spire’s private revenues (through self-pay and private medical insurance) grew 5.1% between January and June 2024.

At the moment, there are 7.5m people waiting for NHS treatment. This will take a long time to clear, giving Spire excellent earnings visibility.

As Britain’s elderly population grows, healthcare businesses like this have significant profits potential over the longer term too. The Office for National Statistics believes one in four Brits will be aged 65 and older by 2050.

I think Spire’s a top stock to consider, even though medical staff shortages (and their impact on costs) remain a threat.