fixedincomeinvestor is a good site for bonds. With longer dated Gilts (bonds) the price can be very volatile ...https://www.fixedincomeinvestor.co.uk/x ... &groupid=3
as in effect a high number of fixed income payments are being priced according to current present day yield, such that if yields change even a little the collective sum of those results in a associated large adjustment move in the bonds price.
As bonds near maturity, when a fixed repayment amount will be paid, so the price tends to stabilise near that amount, so the bond has low price volatility.
With longer dated bonds as yields rise so prices decline; Or as yields decline so prices rise. Similar to stocks (as interest rates rise so stock prices tend to decline such that their dividend yield rises). Another factor however is that when fear of stocks rises and shares are sold to buy bonds so bond prices can spike in the opposite direction to stocks - exhibit a inverse correlation. When later greed is more prevalent and bonds are being sold to buy stocks again a inverse correlation can arise. Holding some of both stocks and bonds tends to smooth the overall portfolio volatility.
Some stocks are less volatile than some bonds, and sometimes less rewarding than bonds. A blend of both is generally seen as being a more appropriate asset allocation than either all stock or all bonds alone.
This is US data, but similar might be seen for UK data, where two thirds stock, one third bonds broadly compared in total return to 100% stock, but where holding some bonds helped reduce overall portfolio volatility along the way https://tinyurl.com/11xobbng
The tendency is that all-stock often tends to have pulled-ahead, but periodically steps back down to compare or even lag a stock/bond blend. A significant risk element is start date, buy in at a relative high and that can severely impact overall investment reward outcome. When started with a stock/bond blend that early days risk factor is somewhat mitigated. That's more relevant however to a large lump sum being invested at a single timepoint. Being young however you are more inclined to drip feed into holdings over time (savings), such that start date valuations risk is equally diversified. However even still, if you can achieve similar rewards with less volatility (which is often perceived to be 'risk'), then the better risk adjusted reward is generally opined to be the better choice.
Given low yields/inflation/interest rates however, and the prospect for long dated bonds bought at such levels is far far lower than if bonds were being bought during a period of high interest rates/inflation. Personally at present interest inflation rates I favour a more equal three way split of FT250, US stock, gold (£, $, global currency .... small, large stock blend along with a commodity type asset allocation). For me, 50/50 stock/gold is comparable to a volatile global currency unhedged bond. Such a asset allocation IMO is appropriate across all age ranges and style (saving or in drawdown). If interest rates/inflation were north of 10% I'd be more inclined towards a stock/bond asset allocation.