1. Introduction  
2. The data: PGS metallicity and Gaia RVS orbits  
3. The sample: Data selection  
3.1. Gaia DR3 quality cuts  
3.2. Pristine DR1 quality cuts  
3.3. Stellar population quality cuts and isochrone filtering method  
4. Validations using spectroscopic surveys  
4.2. Estimating contamination in the isochrone filtered PGS  
4.3. Impact of the spectroscopic contamination  
5. Statistical decontamination of PGS  
5.1. V ϕ - [Fe/H] space  
5.2. Action space  
6. VMP stars on disc-like orbits  
6.1. Trends in the spatial distribution  
6.2. Asymmetries in the decontaminated PGS  
6.3. Insights on the [Fe/H] lower boundary  
7. Summary and conclusions